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33fp3v
|
what's going on in my body when it suddenly decides to tell me i'm super hungry?
|
Five minutes ago I wasn't thinking about food. Now I feel like I could eat an obscene amount of noodles.
What's that feeling in our stomach that we instantly recognize as hunger?
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explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/33fp3v/eli5_whats_going_on_in_my_body_when_it_suddenly/
|
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"Basicly, there's a part of your brain, called Hypothalamus, that observes the bloodsugar level in your blood. And when it gets low, it sends out signals to other parts of your brain to find food.\n\n\nThe other way around, it also notices when you eat something, and rewards you with a satisfactory feeling, especially if you are hungry."
]
}
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[
[]
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9lv64p
|
Why is wireless charging so inefficient?
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askscience
|
https://www.reddit.com/r/askscience/comments/9lv64p/why_is_wireless_charging_so_inefficient/
|
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"Because we don't control the way the energy propagates from the source. It just does so according to the rigid laws of EM. \n\nThe simplest example of the phenomena is to take a flash light and shine it at a wall up close and notice how intense the illumination is. Then step back a few feet and watch how quickly it dulls out. \n\nThe energy transmitted via wireless charging scales by 1/r^(4). So if you double the distance between the charger and the chargee then you witness the power transmitted drop to 1/16th of the former amount. There are ways to make this better, but we're talking by small percentages. We can't avoid this effect as a whole. "
]
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2n2djd
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why do we elevate a sprained ankle? isn't blood good for it? why should we be draining it away from the injury (if that's the point)?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2n2djd/eli5_why_do_we_elevate_a_sprained_ankle_isnt/
|
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"Good question. Also makes me wonder about anti inflamatory medicine.. Isn't inflamation a part of the healing process?..",
"Blood is good for it, but the amount of blood that causes the swelling isn't. Too much blood can put undue pressure on the injury, which can slow the healing process. Combined with the fact that modern medicine has stuff we can take to help the process along, and the excess of blood isn't necessary in the least, and having it elevated allows it to rest, which is most important.",
"These are all wrong so far. Blood doesn't 'cause' swelling. It's a result of biochemical pathways due to localized tissue injury.\n\nTissue injury (in your case, an overstretched tendon) produces a vascular response which does a bunch of crazy manipulations to the diameter of your various blood vessels around the injury to help you heal. The biochemistry pathways involved also do a bunch of stuff to regulate all the manipulations of the vascular system. They also function to produce pain if you try to move as a way of trying to avoid further injury to the area. \n\nAnti inflammatories are taken to block some of the pathways. Which causes less inflammation.\n\n\nYou elevate your ankle because the swelling causes an increase in resistance to your blood vessels. The arteries delivering blood are fine. They have plenty of pressure from the heart. The blood pressure in veins on the other hand is a lot lower, and the force of gravity from an elevated sprain ankle helps the blood not pool in the veins of your foot. \n\nEdit: Forgot to include the purpose of inflammation - (1) Localize damage (2) Remove Damaged Tissue (3) Produce Healing. "
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agn62d
|
Why did the Pope move to Avignon?
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I'm reading up a bit on the Mercenaries in Italy in the late 1300's, and the book was mentioning one of the reasons the mercenaries were there is because earlier they took Avignon and the pope hostage, and afterwards the pope hired them to go into Italy to fight the city states. I know this is a hugely simplified story, but it got me wondering, why did the Pope move from Rome to Avignon? Was it purely because it was a French pope and French controlled? Was there a problem with Rome?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/agn62d/why_did_the_pope_move_to_avignon/
|
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"‘Ubi papa, ibi roma (Rome is where the Pope is)’: This is a famous quote from the word of one of the Avignon Popes, Urban V (r. 1362-70). Nevertheless, this passage can actually imply several aspects of the Papacy during this period as well as its pre-history, not only the famous representation of notorious ‘Babylonian Captivity of the Papacy,’ roughly based on the discontent of the contemporary Italians. Especially French researchers have revaluated the institutionalization of the central organization as well as the popes themselves in Avignon for long since WWII, but this trend of research apparently does not be shared out of medievalists, as rather classical evaluation by Reinhardt, specialized in Early Modern Papacy, shows (Reinhardt 2017: 389-432, esp. 389-94). I summarize some backgrounds of the topic below: \n\n & nbsp;\n\nThe relationship between the Pope and Rome had been regarded as ‘troublesome often’ since the late 11th century. To give an example, the Roman ‘Senate’, in fact a newly established city commune of Rome in 1143, sometimes opposed the popes in 12th century and forced them to conclude and renew a settlement on the city governance. Several popes in the 13th century used to stay away from Rome during summer, and instead resided in some cities like Orvieto or Viterbo in the Papal States. In other words, short to middle term absence of the Popes from Rome had been no longer regarded as exceptional by the 13th century. \n\n & nbsp;\n\nThis problematic relationship worsened further in course of the 13th century: The rising Roman aristocratic families like the Caetani, the Colonna, and the Orsini earnestly advanced into the college of the Cardinals, electoral body of the new pope. The power struggle among these noble families also affect the factional division within the cardinals. Even within the same family, some cardinals in fact sometimes opposed each other. The advancement of the Southern Frenchmen into the cardinals, and into the seat of the Pope like Clement IV further complicated these power struggles already in the late 13th century. Thus, the Frenchmen came into the scene of Papal policy before the Avignon Papacy period. \n\n & nbsp;\n\nThis partly owed the political situation of the time: the popes at first allied with the family of Anjou in France to suppress the Hohenstaufens, son of former Emperor Frederick II (d. 1250). Soon, however, Charles of Anjou (d. 1285), younger brother of King Louis IX of France (d. 1270) and now king of Naples, freed the control from the Papacy and acted as he liked. He and his successor also tried to intervene the papal election. And at last, the factional conflicts in the Northern Italian cities, the Guelphs and the Ghibellines became also problematic during this period; While the former can be also tagged as ‘pro-papal factions,’ the ongoing factional power struggle within the cardinals also affected this conflict in the cities so that the whole faction could get in step each other. In short, no one could control these highly complicated circumstances in Italy at that time. This political chaos in Italy indeed culminated in the pontificates of ‘Angel Pope’ Celestine V (r. 1294) and notorious Boniface VIII of the Caetani (r. 1295-1303). \n\n & nbsp; \n\nThe conclave in 1305 must have been divided in ex-Boniface and pro-French factions: The new Pope, Clement V (r. 1305-1314) was, so to speak, everybody’s friend, or the least disliked to everyone. He was ex-archbishop of Bordeaux, Bertrand de Got, brother of Cardinal Béraud. Contrary to general assumption, Clement-Bertrand was not just a political pawn of the king of France, Phillip IV the Fair. Bordeaux around 1300 was a kind of enclave in the kingdom, governed by the king of England (as a French aristocrat). Clement indeed kept in good contact in good contact both with Phillip the Fair and King Edward I of England, though these two kings had just begun to oppose each other over the former’s jurisdiction of the former to Gascony, the latter’s fief, since 1294. Thus, the new pope had been set in very difficult political positions, not only in Italy, but also in France from the beginning. He prioritized the urgent circumstances of France to the more difficult ones in Italy. \n\n & nbsp;\n\nRollo-Koster also argues, however, that Clement had in fact another, more important concern for all the Latin Christendom: the revival of the Crusade in the Levant, where the last Christian foothold had been recently lost to the hands of the Saracens (Rollo-Koster 2015: 34). It is true that he made many concessions to Phillip the Fair of France, but it was not just because of his origin, but rather to achieve this political goal, by allying every powerful ruler as much as he could. From this point of view, he dared to sacrifice old and not so convenient Templers for buying support from a king of France, arguably the most powerful ruler at that time in Medieval West. \n\n & nbsp; \n\nIn a sense, the location of Avignon itself was convenient to almost everyone as the new Pope Clement himself was, certainly except for the Italians. While nominally in Holy Roman Empire, Avignon was on the crossroads and easily accessible to Bordeaux (his homeland as well as the power base of king of England), the kingdom of France, and further, to Iberian Peninsula. Above all it was free from the power struggles among the Roman aristocratic families as well as hot summer that sometimes forced the popes to stay away from Rome. Clement is also famous.....rather notorious for his preference of recruiting his fellow Frenchmen. We can interpret this papal personnel policy as a sign of his wish to control the power struggle within the cardinals by eliminating the possible Italian factional influence as much as possible (Rollo-Koster 2015: 34f.) In this city, the pope could build more stable, permanent administrative institutions supervising all over the Latin Christendom rather easily than Rome (Schimmelpfennig 1992: 199-204). \n\n & nbsp;\n\nSelected References: \n\n* Reinhardt, Volker. *Pontifex: Der Geschchte der Päpst von Petrus bis Franziskus*. Munich: C. H. Beck, 2017.\n* Rollo-Koster, Joëlle. *Avignon and its Papacy, 1309-1417: Popes, Institutions, and Society*. Lanham: Rowan & Littlefield, 2015. \n* Schimmelpfennig, Bernhard / James Sievett (trans.). *The Papacy*. New York: Columbia UP, 1992. [Original: *Das Papsttum von der Antike bis zur Renaissance*. 6th ed. Darmstadt: WBG, 2009.] \n\n[Edited]: fixes paragraph layout and typos."
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5bvkcb
|
How did soldiers in WW1 stay so motivated?
|
I know there has been mutinies, but most of the time, conscripts were pretty much loyal to their superiors. Considering the horrible conditions of war and extreme likelihood of death or permanent injury, how didn't people uprise against their states in mass numbers to end this war about dying nothing? What would they even be able to do if your whole army turns against you? At least WW2 had a lot of ideological doctrination and brainwashing, but nationalism in WW1 can't be that strong. Also WW2 warfare was not "certain death" like trench warfare of WW1, you could always survive if you were a good soldier and lucky. But I can't wrap my head around the psychology and mentality of a WW1 soldier.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/5bvkcb/how_did_soldiers_in_ww1_stay_so_motivated/
|
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"* [What was the motivation for the continuation of the bloody back and forth fighting of WW1 on the Western Front? Why couldn't they just stay in the trenches and just defend rather than attack again and again?] (_URL_6_)\n* [How did soldiers, generals, politicians, etc. cope with the carnage of the First World War?] (_URL_2_)\n* [With the outbreak of WWI, what caused the stakes of losing the war to become so incredibly high?] (_URL_3_)\n* [What was the psychological impact of putting a man in a WW1 trench?] (_URL_5_)\n* [What were conditions like in trenches on the Western Front?] (_URL_4_)\n* [Given the nationalistic fervour at the beginning of WWI, how many men were 'expected' to die?] (_URL_7_)\n* [What was the public reaction to casualties on the Western Front?] (_URL_0_)\n\n^ These answers I've given previously should be pertinent!\n\n > I know there has been mutinies, but most of the time, conscripts were pretty much loyal to their superiors.\n\nNot everyone that fought in WWI was a conscript. Large numbers of professional soldiers and reservists made up the armies of the Great Powers at the outset, and many thousands volunteered. In the case of Britain, of the 5 million soldiers that served in the army during the war 500 000 were regulars and reservists, 2.2 million were volunteers (200 000 volunteering **after** Conscription was introduced), 800 000 were compelled by the Derby Plan in 1915 but at least were allowed a choice of unit and of when to enlist, and the other 1.5 million were conscripts. Though all the other European powers had conscription, it would be wrong to assume that some would not otherwise be willing to serve. \n\n > Considering the horrible conditions of war and extreme likelihood of death or permanent injury, how didn't people uprise against their states in mass numbers to end this war about dying nothing? What would they even be able to do if your whole army turns against you? At least WW2 had a lot of ideological indoctrination and brainwashing, but nationalism in WW1 can't be that strong.\n\nYour problem here seems to be the assumption that the powers were fighting for nothing. The British were hardly fighting for nothing, having gone to war to aid the Belgians and prevent German dominance of the continent. The French Army fought to defend France, and expelling the Germans was imperative considering that the occupied most of France's mines and a considerable amount of it's heavy industry, in addition to millions of French civilians. Belgium and Serbia go without saying, both countries being occupied and subjected to brutal regimes. The Central Powers could argue, with quite some justification, that they were in a war for their survival, the German, Austro-Hungarian and Ottoman Empires being surrounded by powers that had displayed ambivalence and hostility towards them in the past, even if the fears of 'encirclement' before the war were greatly overblown. Even the Russians could justify their war effort in helping fellow Slavs/Eastern Christians (ex. Serbs, Armenians) escape Germanic and Ottoman rule and to assist their western Allies, while after 1915 they were also fighting a broadly defensive struggle in Europe. \n\nAs for horrible conditions, yes, depending on where you served they could indeed be ghastly and demoralizing. At the same time, the Armies on the Western Front at least kept up a fairly consistent rotation that allowed battalions time out of the firing line, while the positions of the German defenders in the West could be quite homely due to their defensive stance. And armies did face serious problems; Russian morale finally caved-in in autumn 1917, the Austro-Hungarian and Bulgarian armies surrendered in September-October the next year, and the Germans and Ottomans that November. All the same, comradeship, unit loyalty, and belief in the national cause were all essential parts of morale and motivation, as well as an often strong feeling of indebtedness to the 'sacrifices' of the dead. Ideology may have been more overt in WWII, but even here it was not a necessity for combat motivation. Felix Roemer's examination of prisoner interrogations and recorded conversations in POW camps in the US, as well as the research into the German home front in WWII done by Nicholas Stargardt, both indicate that strict adherence to Nazi ideology was not the norm, and that traditional German nationalism combined with Hitler's cult of personality were more common. It also didn't take being ideologically indoctrinated in Nazi racial policy to commit war crimes, as Christopher Browning's famous work *Ordinary Men* showed. In the same way, it didn't take ardent nationalism to believe in the necessity of defending one's homeland during WWI, though Pan-Slav and *Drang nach Osten* sympathies were certainly present among some combatants on the Eastern Front. \n\n > Also WW2 warfare was not \"certain death\" like trench warfare of WW1, you could always survive if you were a good soldier and lucky. But I can't wrap my head around the psychology and mentality of a WW1 soldier.\n\nNor was WWI \"certain death,\" although casualties could be and were often very high in both wars. In fact, casualty rates were far higher in the mobile fighting on the Eastern Front in 1915-16 than on the Western Front at the same time, while casualties in 1914 and 1917-18 in the West outnumbered those of trench warfare in the west in 1915-16. As I demonstrate in [this] (_URL_1_) answer, the Western Front of WWII was far from a picnic, while the Eastern Front of WWII outdid any of the fighting in WWI or WWII for brutality, intensity, and shear loss of human life (combatants and non-combatants alike). If you were a good soldier and lucky, you could certainly survive both wars, and the similarities of the frontline experience and of combat motivation in both wars far outweigh the differences, at least in my opinion. \n\nIf you want further reading, *Enduring the Great War* by Alexander Watson and *The Sharp End* by John Ellis are good places to start. "
]
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[
[
"https://www.reddit.com/r/AskHistorians/comments/3e1mr0/what_was_the_public_reaction_during_the_first/",
"https://www.reddit.com/r/AskHistorians/comments/58seo1/which_one_had_a_higher_weekly_casualty_ratewwi/",
"https://www.reddit.com/r/AskHistorians/comments/47ql41/an_often_said_slogan_about_the_great_war_was_that/",
"https://www.reddit.com/r/AskHistorians/comments/56edpw/with_the_outbreak_of_wwi_what_caused_the_stakes/",
"https://www.reddit.com/r/AskHistorians/comments/3dxlav/what_were_the_conditions_during_ww1_in_the/",
"https://www.reddit.com/r/AskHistorians/comments/4s64oq/what_was_the_psychological_impact_of_putting_a/",
"https://www.reddit.com/r/AskHistorians/comments/57ynt9/what_was_the_motivation_for_the_continuation_of/",
"https://www.reddit.com/r/AskHistorians/comments/3eaz7v/given_the_nationalistic_fervor_for_war_at_its/"
]
] |
|
29xk3g
|
is there an evolutionary reason people think "the good old days" were better?
|
People seem to think the past was overall better than the present, despite all evidence to the contrary. Is there an evolutionary reason this attitude is so prevalent?
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explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/29xk3g/eli5_is_there_an_evolutionary_reason_people_think/
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"there are hundreds of studies in this area. as a whole it comes down to one thing, change. change is not received well by humans because change takes us out of our comfort zones. this can give the feeling of uncertainly and ultimately causes a primal response. a good thing to look at in the 'change curve'. this is the process everyone goes through for every change. generally small changes progress along the curve quicker than large changes and different people take different amounts of time to move along the curve. Large employers have trained HR staff to improve the speed of individuals means of coping with a change in their employment. ",
"It's not so much an evolutionary reason, as just an artifact of how we process our surroundings.\n\nYou see, most of the things that you consider negative about your day to day life are actually fairly minor, but they add up throughout your day. Tiny struggles and annoyances that make you feel like your life is drudgery, worthless, and more of a pain than it's worth. Nothing major, but almost constant annoyance. Death by a thousand paper cuts, to steal a phrase. \n\nGOOD THINGS, however, tend to come in more discrete moments. They are usually bigger, more memorable, and more notable. You can remember when various good things happened in your life. They are the things that you hope and pray for every day. That promotion at work. Getting married. Having children. Getting a new car. Your team winning the championship, etc...\n\nSo, you can see how negative things are generally smaller in amplitude, but higher in frequency, whereas positive things are generally bigger in amplitude, but slower in frequency.\n\nThis leads to the curious situation where, as time passes, you forget the negative things more quickly than you forget the positive things. The negative things weren't notable individually, and so you can't really recall them on an individual basis. You CAN, however, make individual notice of good memories. They were more impactful individually, and made stronger memories.\n\nSo, think back 15 years ago. You can't possibly remember, or feel the emotions, of the day to day dreariness that you felt. The frustration of traffic. The long afternoons. The headaches. The annoyances. But you CAN remember the major victories. The triumphs. The love. The adrenaline. All the memories that make you proud of who you were, and what was going on.\n\nThe further you go back, the less you can recall the things that truly make you dread each and every day. Things that sap the life out of you this very day. You eventually won't be able to recall them anymore, and in the future you will wish to return to this very day, back when you \"didn't have the problems that you do now\".",
"Not everything has to have an evolutionary reason.",
"I'm just spitballing here, getting philosophical. But perhaps we need to believe the Good Old Days were better so that we can believe the future might also be better. We need to at least think its possible that the world might not suck (one day), and believing that it didn't suck in the past proves to your mind that a non-sucky world is at least possible, even if its not happening right now. If we saw our lives as they really were, one unmitigated shitshow after another, we'd probably all kill ourselves. "
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ez23y3
|
how did banks greatly contribute/ cause to the great recession in the 2000’s?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/ez23y3/eli5_how_did_banks_greatly_contribute_cause_to/
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"They made a lot of very bad lending decisions. They gave people money in exchange for pieces of paper saying they will get paid back. The people they gave money to a lot of times weren’t going to be able to pay it back, but the banks still gave them the money. Then, they sold all of their pieces of paper to their bank friend. The other bank then took all the pieces of paper and turned them into a super package of papers and sold pieces of the super package to their bank friends.\n\nWhen the people couldn’t pay the money back, all of the super pieces of paper were worth nothing.",
"They didn't care that they were giving loans to people who would default because they sold the risk to others who then repackaged. Also a lot of hubris thinking that nothing bad would ever happen and when they realized it would all go south they bet against the crap loans they originally sold to make money",
"The people in this thread have answered it well. I'm no expert at this subject at all, but the movie \"the big Short\" seemed to capture everything pretty well and describes the different factors at play if you want an entertaining movie to get more info.",
"1. Loaned money to poor people who couldn't pay. \n2. Resold that debt to others to collect\n3. Repeat",
"Before the recession, the value of homes were growing at very fast rate. So, many banks gave out loans, think that even if they didn't get money back from the loan, they could sell the home and get it back and make profit.\n\nThey started giving \"sub-prime loans\" with really high interest rates to people with bad credit. Many people couldn't afford their loans, defaulted, and the bank was out of money. They took possession of their homes. \n\nThe demand for homes went down, however, and caused their price to go down too, so selling them didn't make enough money back. The banks started failing because they lost so much money on the loans.",
"They made millions of home loans to people they should have known would not be able to pay them back. In many cases they were quite aware they would not be getting paid.\n\nThen \"securities\" were created which were basically like a loan that uses a bunch of smaller loans as collateral. These smaller loans were those risky mortgages I mentioned above. So the big securities were worthless but most people didn't know they were worthless.\n\nOne small stock market crash and it caused a cascade of home loans to go into default, causing the securities to fail, causing banks to fail, crashing the economy.",
"OK, the best way to discribe this is to discribe the \"old\" way and then compare it to the new way.\n\nIn the old days, a bank would lend money. They would then get paid back according to the terms of that loan. So they would lend $100,000 on day 1, and it would take 20 years to get it all back in monthly payments. The up side here is they would receive interest along the way.\n\nSo if someone failed to repay the loan, it's the bank that actually lent the money that would suffer the loss. So there was a strong incentive to only make good loans. \n\nThis is slimier to how it works today, banks lend money to people. They decide who to lend to and what interest rates to set. The problem is, immediately after lending the money the banks would sell the loan to someone else. \n\nThis transfers the risk of the loan to a new person (or instution). And normally this would mean this new person requires a higher interest rate because they did not have a hand in setting the original terms of the loan, so they are by default less confident in the repayment of the loan. But there was a step (or two) that prevented this from happening.\n\nFirst thing is that the person who bought the loan actually bought hundreds of loans. They take those loans and bundle them all together. So instead of 1 $100,000 loan, they have 10, 20 or even 100. They then take that bundle of loans and cut it up into smaller bits and they resell those bits to other investors.\n\nSo if I have $100,000 invested in loans, what I actually have is 1/100th of 100 different loans. So I own $1,000 of each of 100 different $100,000 mortgages. This spreads the risk around, it's highly unlikely that all 100 of me peaces of loan will default, sure some of them might but most won't. This effectively lowers the risk of the initial debt.\n\nSo to recap. Someone bought the banks loan, they bought many of them. They mixed the loans all together then cut the mix up into peaces again and sold the peaces. These new loan peaces are considered very low risk because the risk of default is spread among a large number of borrowers. \n\nThere's one more thing. Even if someone defaults, we are talking mortgages here and mortgages have houses as collateral. So even if someone defaults their house is taken and resold. Since (prior to 2008) home prices always go up, the value of the collateral is \"always\" more than the value of the loan itself. \n\nEVEN IF everything failed, these little investments have insurance on them! So the insurance company pays if everything goes wrong with one of these investments. \n\nThis allows the financial industry to sell these new things (loan bits) as VERY, VERY safe investments. There are third parties that have basically certified these investments as virtual guarantees. \n\nInvestments that are considered to be basically zero risk have a very special place in the way banking works in a modern system. Banks are not required to hold onto all of the money you deposit into them. They are allowed to make loans with the money, but they are required to hold onto a portion of it. This is known as fractional reserve banking and I won't get into the details of it, just know it exists. The banks are required to hold a portion of their deposits in... wait for it... very safe investments. \n\nSame thing with insurance companies. They might write policies that would see them paying our $50,000 if it fails, but they don't need to have all of that cash on hand at any given time because every policy is unlikely to fail all at once. So they only need to have cash on hand for a fraction of their total oblations. They keep that cash in, very safe investments. \n\nSo now for the problem. All of this safety and risk assumes that a small number of the loans go bad. If they go bad there's insurance and the value of the house there to recover any potential loss. Even if there is some loss it's all spread around to different investors so no one person takes a big hit. \n\nAnd so along comes 2008. Because the banks lending the money are not the ones taking the risk of repayment the banks get a little too free with lending the money. So they are giving loans to people who are highly unlikely to repay them. But remember, that's OK because home values \"always\" go up, and there's insurance on these things anyway!.\n\nExcept... home prices do NOT always go up. When people start to fail at repaying their mortgages there's all of a sudden a whole bunch more homes on the market. Banks see that happen so they tighten up their lending a little bit and that removes some buyers form the market. A high supply, and a lack of buyers activates the laws of supply and demand, and that means prices must fall. So home prices start to go down.\n\nBut there's still all these \"investments\" out there in mortgages who's risk level was determined assuming that home prices will not fall. All of a sudden these investments are losing money and they are held by people who absolutely cannot have losses in their accounts.\n\nInsurance companies start having to pay out on policies, but they themselves have held these investments because they thought they were safe, so they don't actually have the money to cover everything they have promised. AIG, one of the largest insurance companies in the country goes under. \n\nThe banks who were making these mortgages all of a sudden can't sell them like they used to. They are forced to hold onto them. So they start making considerably fewer mortgage deals. That means fewer home buyers and THAT means lower home prices (again). This means that there's lots of people out there who have mortgages that are higher than the value of the underlying property, so these people stop paying the mortgage (because why would you). This causes these properties to foreclose and go onto the sale market, that means more homes for sale and home prices drop, again. \n\nThose chopped up mortgage investments are now worth considerably less than people thought they would be. It's like a series of dominoes falling, one after the other. Insurance companies, banks, retirement funds and all kinds of other investors are all of a sudden holding something they thought was low risk but was actually fairly high risk. So they are all freaking out about their investments and the losses they are taking. \n\nBanks now can't lend money because they don't have enough cash on hand to cover the fraction they are required to keep. Insurance companies can't pay out on policies for the same reasons. Home owners can't sell homes because no one can get a mortgage and people with mortgages are refusing to pay them because the house is not worth what they expected it to be. \n\nIt all came crashing down, hard and fast. Very few people saw the inherent flaws in the system that had been build. The main flaw being that the person who decides to lend the money is not the person on the hook if that choice turns out to be a poor one."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[],
[]
] |
||
17sxce
|
What were the major problems which held back the development of
the French economy in the late 1700s?
|
I'm currently studying year 12 history, focusing on France's revolutionary period and I am completely lost.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/17sxce/what_were_the_major_problems_which_held_back_the/
|
{
"a_id": [
"c88jle6"
],
"score": [
2
],
"text": [
"It's important to note geographical bad luck meant it lacked the plentiful and easily accessible coal, iron,etc that allowed Britain to industrialise. It then entered the Eden Treaty with Britain which lowered import duties on British manufactured goods and as a result was swamped with cheap British goods placing strain on their own underdeveloped manufacturing base."
]
}
|
[] |
[] |
[
[]
] |
|
cm4cqp
|
why do some diseases kill so quickly? wouldn’t it be more advantageous to be super slow and stealthy so you can get the biggest bang for your buck out of your host?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/cm4cqp/eli5_why_do_some_diseases_kill_so_quickly_wouldnt/
|
{
"a_id": [
"evzuxok"
],
"score": [
10
],
"text": [
"The majority of those diseases - often called plagues - are not natural to humans. They're diseases that have jumped the species gap from some other species to humans.\n\nWhat's the equivalent of a cold to an animal may be far more lethal to the biology of a human. As such they didn't evolve for humans and don't exhibit the kind of behaviour you'd expect of something that wants to survive.\n\nAside, and this comes up often, but \"best bang for buck\" isn't the goal of evolution. Evolution is only about surviving and procreating. A disease that only lasts a week, but has an excellent chance of infecting additional people during that week, is just fine from a \"propagation of the disease\" standpoint."
]
}
|
[] |
[] |
[
[]
] |
|
f16jan
|
how does a long exposure picture (10 plus hours) of other galaxies work when the earth in constantly spinning?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/f16jan/eli5_how_does_a_long_exposure_picture_10_plus/
|
{
"a_id": [
"fh29edy",
"fh2gvqu"
],
"score": [
12,
2
],
"text": [
"Normally the telescope/camera is attached to a motorised tracking device/\"tripod\" which ensures the object being photographed remains in the centre of the image.",
"There are two common ways of doing this.\n\nThe traditional way is to slowly move the camera so that it stays aligned with the stars as they move. \n\nAn alternative way is to use some computer trickery. Rather than have the camera take a single long exposure, you can split the same time into a series of shorter exposures - each short enough that they won't show any movement in the stars - and then combine these together on the computer, aligning each image so that the stars all line up.\n\nProblems will appear if you want to take a long exposure showing both landscape features and the stars above, so this would normally be handled again with multiple exposures in the editing stage, with tricks like using the foreground from on image, then deleting the foreground from all the other images to let you line up all of the composite sky shots separately from the ground."
]
}
|
[] |
[] |
[
[],
[]
] |
||
4w5unk
|
Why does Zinc only rust on the outer layer while iron rust all the way through?
|
askscience
|
https://www.reddit.com/r/askscience/comments/4w5unk/why_does_zinc_only_rust_on_the_outer_layer_while/
|
{
"a_id": [
"d649tdu",
"d64hs02"
],
"score": [
13,
6
],
"text": [
"The product of the corrosion (zinc oxide) forms a protective layer preventing further oxidation of the zinc, whereas the iron oxides which are a result of iron rusting are fragile and flaky and don't form a protective layer.",
"Zinc corrosion is tightly packed due to the molecular structure of zinc oxide. Think of it like lizard scales, seperate but tightly packed and durable. It doesn't expand much and once the outer layer is covered, no more oxygen can get through to attack the inner layers. Iron oxide(rust) expands exponentially during the formation of its crystalline structure causing flaking and irregular pieces. It's also much softer and susceptible to outside forces. The loose structure and flaking allows for deeper penetration by oxygen causing more expansion opening up deeper layers and so on. Hope that helps."
]
}
|
[] |
[] |
[
[],
[]
] |
||
8ohvee
|
why is it that butterflies don't need to learn how to fly ?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8ohvee/eli5_why_is_it_that_butterflies_dont_need_to/
|
{
"a_id": [
"e03kgph",
"e03wn6l"
],
"score": [
7,
2
],
"text": [
"They are little pre-programmed organic machines. Just as spiders don’t have to learn how to weave a web, and crickets don’t have to learn to chirp. \n\nLower level insects are reacting to stimuli and running their software loops (with an ultimate goal / focus on successful reproduction). ",
"If you go a little bit abstract and think about it, the process of learning is needed where the necessary information for survival cannot be contained in the DNA.\n\nYou're born with the necessary muscle movements for your heart for instance, but you have to learn spoken languages for survival.\n\nIn that sense, living things that are simple enough are born with the entire information they need to survive; from the instructions for their body plans to the actions that those bodies will perform.\n\nIn Ancestor's Tale, Dawkins elaborates on an experiment where beavers in isolation start \"mime-building\" dams in thin air. The action is hard wired in them, so even if there are no rivers or logs around, they are compelled to continue to the action; alluding to the fact that just like morphological characteristics, behavioral characteristics are also passed down genetically.\n\nSo for the butterfly, flight is literally in their DNA."
]
}
|
[] |
[] |
[
[],
[]
] |
||
1mzywl
|
What would the uniform of a British officer in the North American frontier have looked like between 1750-say 1800?
|
I'm mostly curious about any differences between the standard uniforms of the British military of the time and what might have been worn along the Western frontier of British influence at the time.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1mzywl/what_would_the_uniform_of_a_british_officer_in/
|
{
"a_id": [
"cceazfh",
"cced28i"
],
"score": [
2,
4
],
"text": [
"British regulars wore uniforms that were similar to the ones worn by General Thomas Gague's troops when the assaulted Bunker Hill. During the French and Indian wars, General Braddock and General Forbes both commanded entire regiments of British troops that wore uniforms not much different than the ones in this painting of the Battle of Bunker Hill. \n_URL_0_ \n If you use Google Image, search for General Bouquet. You will see a color painting of General Bouquet, Alexander McKee and three other British officers negotiating with an Indian leader during the Pontiac rebelion of 1763. The url for that painting is way to long for me to even try and post here. During the Revolutionary War, the British depended on their Indian allies. They sent a small number of officers to organize these allies. Alexander McKee was the British Agent that worked with the Shawne. There is a sepia tone image of this same painting on the cover of the biography about Alexander McKee. ",
"Officers uniforms are substantially more difficult to generalize than that of the men under their command- By virtue of the fact that officers had their uniforms privately tailored and not issued *en masse*- The first document regulating officers' dress was issued in 1768 (which we will come to later). \n\nHaving said that- An officer's uniform of the Seven Years war consisted of a somewhat voluminous scarlet coat with deep, slashed, cuffs and wide lapels. Cords on the right shoulder indicated rank. Beneath the coat was worn a waistcoat, either in scarlet or the facing color of the regiment. \n\nHis accoutrements included a gorget (either gold or silver depending on the color of lace worn by the regiment), a red sash draped across either the left or right shoulder, and a sword belt worn beneath the waistcoat. \n\nHis breeches were either of red or blue, the latter being worn by Royal Regiments. Legwear was either white gaiters (usually restricted to parade use), spatterdashes, or boots. \n\nHeadgear consisted of a tricorne hat, laced in gold or silver, for battalion companies, with a black Hanoverian cockade. Grenadiers wore a distinguishing high mitre cap. Light infantryman, raised for service in North America, wore small leather caps with turned up peaks and a rear flap to protect the ears and back of the neck- Though they initially improvised by removing the brims of their tricorne caps. \n\n[Lt-Col. Francis Smith, 10th Regiment, c. 1764](_URL_12_)\n\n[Colonel Alexander Campbell, 1763](_URL_11_)\n\n[Captain William Baille, unknown date](_URL_0_)\n\n[Robert Clive at Plassey, 1757](_URL_15_)\n\n[Battalion Officer](_URL_7_) from David Morier's *The Battle of Culloden*, 1746\n\n[Captain Robert Orme, Coldstream Guards and aide-de-camp to General Braddock, 1756](_URL_2_), note the buff riding breeches- worn with riding boots- and similarly colored waist-coat. \n\nFrom 1768, uniforms assumed a tighter and generally neater appearance. The coat itself assumed a distinctive tail-coat look, known as a coatee. This garment would serve as the full-dress uniform of British soldiers, albeit with many modifications, until 1855. Coat cuffs were small and circular in shape, lined with buttons and laced in the regimental pattern. Lapels were in the facing color, with buttons edged in gold or silver. Tails hung in the rear, lined white, with skirts permanently hooked back. Coat tails were cut short for light infantry. Collars, now present in the uniform, were turned down. The coat cut away to reveal the waist-coat, now plain white (or buff for certain regiments, red for light infantry). \n\nAccoutrements remained broadly similar, though a new form of rank distinction came into use with the 1768 warrant. Epaulettes- either in gold or silver- were worn on the right shoulder for battalion company officers, on both for Grenadiers and Light Infantry. Majors and above wore epaulettes on both shoulders. The sash was now removed to the waist. The gorget remained in use. The sword belt was worn on the right shoulder, over the coat on-duty, under the coat off-duty. \n\nBreeches, like the waistcoats, were now white. Over these were worn black leather boots or high-topped black gaiters- though officers in North America often replaced these with shoes and half-gaiters, as seen in the portrait of the officer of the 4th regiment below. \n\nThe tricorne hat of the battalion companies had its fore gradually pushed up, to the point where it assumed a more bicorne shape. Grenadiers shed their cloth mitres for imposing bearskin caps. Light infantry, reintroduced to the service in 1771, wore a variety of small caps.\n\n[Lieutenant Robert Hamilton-Buchanan](_URL_16_) in a Grenadier's Uniform\n\n[Lieutenant Colonel Sir Charles Stuart, 1779](_URL_18_)\n\n[Lady Louisa Lennox and various officers of the 25th Regiment in Minorca, 1769-1771](_URL_9_)\n\n[Officer of the 4th Regiment of Foot, 1780](_URL_14_)\n\n[Center Company Officer, Royal Welch Fusiliers](_URL_1_) showing the Hanoverian cockade in marvelous detail.\n\n[Captain John Hayes St Leger, 1778](_URL_8_)\n\n[Captain Thomas Hewitt, 10th Regiment of Foot](_URL_5_) showing the light infantry's red waistcoat.\n\nIn 1797, the coat was fastened to the waist. The coat could now be worn in three ways- fastened up the center with hooks and eyes revealing broad lapels in the facing color, or buttoned over- hiding the lapels and assuming a double-breasted look. It was also common to see the top lapels unbuttoned, revealing a part of the facing color. By this point, the cocked hat had assumed an entirely bicorne shape, and was frequently worn 'fore-and-aft'. This uniform persisted until 1812. \n\n[Captain John Clayton Cowell, 1st Regiment of Foot, 1796 ](_URL_3_)\n\n[Officer of the 56th Foot, 1799](_URL_13_)\n\n[Colonel Fitch and Sisters, 1800-1801 by John Singleton Copley](_URL_6_)\n\n[Captain Charles Davy, 29th Regiment, 1800-1811](_URL_4_)- showing a coat with the top lapel unbuttoned. \n\n[Major James Dunsmore, 1804](_URL_10_)\n\n[Mounted Officer, 1804](_URL_17_)\n\n***\n\nThat's regulation dress- What might actually be worn in the field, especially somewhere as far afield as North America, is a different matter entirely. \n\nSome of the earliest adoptions to the terrain faced in North America were seen during the Seven Years War- Earl Howe, one of the early proponents of light infantry tactics, ordered his men \"to cut the Brims of their Hats off; no Person, Officer or Private, be allowed to carry more than one blanket and a Bearskin, no Sash or Sword, nor even Lace... the Regulars have left off the their proper Regimentals, that is, the have cut their Coats so as scarcely to reach their Waist... every Officer to carry his own Pack, Provisions.\" (quoted in Barthorp, pg. 40)\n\nDuring the American Revolution, there were frequent campaign adaptions- Though very little visual evidence exists to determine just what officers looked like. Officers of Burgoyne's Army at Saratoga, for example, wore single-breasted jackets, worn with breeches and slouch hats. In the winter, soldiers might wear a sheepskin-lined Canadian overcoat or *Capot*. \n\nFor more information on the subject of the dress of the British Army in North America, you might want to check out the Osprey Publishing Titles *The British Army in North America 1775-83* and *British Forces in North America 1793-1815*\n\n*** \n\nSources:\n\n* Barthorp, Michael. *British Infantry Uniforms since 1660* (Blandford, 1982)\n\n* Franklin, C.E. *British Napoleonic Uniforms* (History Press, 2008)\n\n* Mollo, John. *Uniforms of the American Revolution* (Blandford, 1975)"
]
}
|
[] |
[] |
[
[
"http://usarmy.vo.llnwd.net/e2/c/images/2012/06/13/251411/original.jpg"
],
[
"http://ichef.bbci.co.uk/arts/yourpaintings/images/paintings/brhm/large/es_brhm_bns_041_014a_large.jpg",
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"http://ichef.bbci.co.uk/arts/yourpaintings/images/paintings/ng/large/ng_ng_ng681_large.jpg",
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"http://upload.wikimedia.org/wikipedia/commons/1/1f/Copley-Col-Fitch-sisters-1800.jpg",
"http://i.imgur.com/BITcFQ6.jpg",
"http://ichef.bbci.co.uk/arts/yourpaintings/images/paintings/wadd/large/ntiv_wadd_2259_large.jpg",
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"http://ichef.bbci.co.uk/arts/yourpaintings/images/paintings/gm/large/gl_gm_2240_large.jpg"
]
] |
|
3qd7y9
|
how should i interpret the new finding "processed meat has been linked to an 18% increased risk for colon cancer"?
|
Does this mean that I'm 20% more likely to get colon cancer than someone who does not eat processed meat? Or does it mean my risk of colon cancer (~3%) has increased 18% (to ~3.6%)?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3qd7y9/eli5_how_should_i_interpret_the_new_finding/
|
{
"a_id": [
"cwe5boi",
"cwe5eaq",
"cwe5yx8"
],
"score": [
7,
3,
2
],
"text": [
"According to BBC, it's the latter: \n \n > In the UK, around **six out of every 100** people get bowel cancer at some point in their lives. \nIf they were all had an extra 50g of bacon a day for the rest of their lives then **the risk would increase by 18% to around seven in 100** people getting bowel cancer. \n\"So that's one extra case of bowel cancer in all those 100 lifetime bacon-eaters,\" argued Sir David Spiegelhalter, a risk professor from the University of Cambridge.\n",
"As pointed out by ABC New's \"Health Corespondent\", it raises the probability of getting colon cancer from (IIRC) 5% to 6%.\n\nSo, unless you are eating lots of meat every day, which has other negative consequences, you should be ok.",
"Here's a great [article](_URL_0_) that explains.\n\nOn a personal note, I by no means feel bad about killing an animal for food, but westerners eat way too much meat processed or no. It's harder on the environment and your body. Also, you might actually learn something by trying to decrease your processed meat consumption without spending more on food. And learning is cool."
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.vox.com/2015/10/26/9617928/iarc-cancer-risk-carcinogenic"
]
] |
|
3apm8u
|
why spanking your children is becoming less accepted by society.
|
My parents tell me all the time they got beat with a belt, a paddle, a stick, just about anything laying around for punishment, but most parents don't spank their kids at all anymore.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3apm8u/eli5_why_spanking_your_children_is_becoming_less/
|
{
"a_id": [
"cser99y",
"cserf07"
],
"score": [
5,
4
],
"text": [
"It's illegal to beat anyone, why would it be legal to beat your child?\n\nAlso it's a bad tool to actually instruct your child with. Think about it like this, 2 children join their parents for a birthday party. Both kids misbehave, so the parents of kid A spanks him, but parents of kid B explains to him why what he did was wrong and that he wouldn't want others to behave like that to him.\n\nNext time both kids behave. But here is the thing, once the kids are no longer with the parents kid B still behaves good, as he have actually learned why he should behave. While kid A that only behaved so his parents wouldn't hurt him, why would he keep behaving when the threat of his parents is no longer around?",
"Because society is realising that this has the potential to cause long-term harm in children. Research has shown that the more a child is hit as punishment during childhood, the more they are likely to hit others - friends, siblings, peers, and so on. Even when only hit a small number of times as a child, they grow into adults who are more likely to suffer symptoms of depression.\n\nAdditionally, spanking doesn't work. When spanked, a child feels vulnerable and frightened - a state of mind which is not conducive to learning. So although they will stop doing whatever it is they've been doing previously (because they are frightened), they won't learn from the experience, and the short-term change in behaviour won't be reflected with any long-term change.\n\nSo - it doesn't work, and it leaves lasting negative effects. Hence why it's becoming less accepted."
]
}
|
[] |
[] |
[
[],
[]
] |
|
1ye2as
|
How were teen pop idols such as Elvis Presley or The Beatles perceived among male teens?
|
I am a huge fan of both and you always hear of the admiration coming from young teen girls. But how were they perceived among men? Was it similar to the way Justin Bieber is very unpopular with men?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1ye2as/how_were_teen_pop_idols_such_as_elvis_presley_or/
|
{
"a_id": [
"cfjq9pq",
"cfjuu54"
],
"score": [
188,
84
],
"text": [
"Apparently the French boys loved the Beatles even more than the girls did. \n\n > Ringo recalled, “These boys chased us all over Paris. Before, we'd been more used to girls. The audience was a roar instead of a scream; it was a bit like when we played Stowe boys' school.” \n\n[George wasn't very enthused about that though, recounting their Parisian tour in 1964](_URL_0_)\n\n > “The French audience was dreadful. We had visions of all these French girls, ‘Ooh La La’, and all that, but the audience, at least on the opening night, was all tuxedoed elderly people and a bunch of slightly gay looking boys were hanging round the stage door shouting ‘Ringo, Ringo!’ and chasing our car. We didn’t see any of the Brigitte Bardot’s that we were expecting.”",
"Bob Dearborn was a DJ [who wrote up an interpretation of Don McLean's American Pie](_URL_0_). In it, he discusses how frustrated those '50s male teens over Elvis:\n\n > Like many young men his age who were turned off by their girlfriends' screaming for Elvis Presley, he embraced an alternative musical idol named Buddy Holly. While there was no question as to Presley's reign as king of rock and roll at that time, Buddy Holly and his music did make important contributions to that era, and influenced many up-and-coming artists, ranging from Bobby Vee to the Rolling Stones.\n\nBuddy Holly would die in a plane crash in 1959 (\"the day the music died\" in American Pie's lyrics, according to this interpretation).\n\nHe continues about the then-contemporary Beatles and how they seemed (by some) to be continuing the Elvis tradition rather than the Crickets:\n\n > Noting the Beatles' continued musical dominance, McLean refers to the \"sergeants playing a marching tune,\" -- the Beatles classic \"Sgt. Pepper's Lonely Hearts Club Band\" album was very big then -- and, although other players tried to take the field, the sergeants refused to yield.\" At this point, McLean also expresses one of this chief complaints about music since the death of Buddy Holly. The line goes something like, \"we got up to dance but never got the chance.\" McLean feels that there is no fun to music anymore because the kids can't even dance to it.\n\nWhether you buy this interpretation or not (McLean himself tends to stay mum on the matter), Dearborn clearly points out that a lot of teenage boys didn't think much of all the shouting over Elvis and the Beatles."
]
}
|
[] |
[] |
[
[
"http://www.triumphpc.com/mersey-beat/beatles/beatles-paris4.shtml"
],
[
"http://user.pa.net/~ejjeff/pie.html"
]
] |
|
28lc2r
|
Pre-settlement North America for dummies.
|
I am looking for a book on native American culture before European settlement. Something moderately basic preferably, as my knowledge of anything native American is practically nil, so I need something that can make a good jumping off point.
Thanks for the help.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/28lc2r/presettlement_north_america_for_dummies/
|
{
"a_id": [
"cic16cn",
"cic1c3m"
],
"score": [
2,
2
],
"text": [
"If you're interested in the Amerindians (natives of both North and South America, sans Inuits and a few others) rather than strictly North America, then I'd recommend Charles C. Mann's \"1491: New Revelations of the Americas Before Columbus\".\n\nIt's popular history and a tertiary source, but unlike many such books, it's generally thought highly of in this subreddit. Search in this sub on \"1491\" and you'll see. I'm not an historian myself, and I found it a great overview. There's probably nothing new to historian's who specialize in this area, but it's a good introduction. According to the reviews here, there are only a few questionable claims.\n\nMann says that he wrote the book because much research in this area over the last few decades hasn't found its way into school curricula or popular history yet. For example, the fact that the landscape that the first Europeans found was often anything but natural, with many aspects of it purposely modified by the Indians. An example is that in Eastern North America the Indians frequently set fires that burned out the underbrush in the forest, because it increased the amount of their favorite game (e.g. deer). It also discusses the controversy over the population of the pre-Columbian Americas. I could name other things that were a surprise to me, but you get the point.",
"\"Native American\" encompasses more than 10,000 years of history on two landmasses stretching from pole to pole; you'd be better served by picking an area, and then focusing down on a specific time period in that area if you want decent information. The AskHistorians Book List has a few books on Pre-Columbian [America north of Mexico](_URL_0_) and a more extensive list on [parts further south](_URL_0_2)."
]
}
|
[] |
[] |
[
[],
[
"http://www.reddit.com/r/AskHistorians/wiki/books/americas#wiki_pre-columbian",
"http://www.reddit.com/r/AskHistorians/wiki/books/americas#wiki_pre-columbian2"
]
] |
|
m8k9u
|
game engines
|
I'm interested in game engines, how they work and what they do. Specifically the graphics engine, but I assume that they bear some similarity to one another.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/m8k9u/eli5_game_engines/
|
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"A game engine is nothing more than a bunch of code/software that handles the \"hard\" parts of making a game work so that the developers can focus on creating gameplay and content.\n\nSome things that a game engine may do:\n\n* Read and write graphics files (3D models, textures, sprites, etc.) and display them on the screen\n* Automate graphical special effects (animations, rotations, lens flare, etc.)\n* Track objects in the game world\n* Detect collision between objects\n* Provide information about frame rates, performance, and so on\n* Control maximum and minimum frame rates\n* Scale graphics to different screen sizes\n* Detect, report, and record input from keyboard, mouse, joystick, controller, mic, or other input device\n\nNot all game engines have the same features. However, they all provide ways that a programmer may interact with the features of the game engine, usually through code libraries containing functions, methods, classes, and event handlers.\n\nIs that clear enough or do I need to elaborate or clarify anything?",
"While EdgeOfDreams already made a pretty good post, its pretty techincal so for the real 5 year olds out there, its like choosing whether I want to play with Legos or Lincoln Logs. They don't provide prebuilt models of what you want to make and only provide a basis for you to expand on any idea you have. This way you dont have to make the building blocks and just start building :) Obviously this is pretty simplified but hope this helps less tech savvy people.",
"Imagine you're playing with dolls / action figures. Every second, you're moving their arms, heads, make sound effects, make them talk, and decide what's going to happen next. When you play, you're the game engine. \n\nThe same thing happens inside a video game -- the game engine knows how a gun sounds, what a car looks like and how it should move. A gazillion times every second, the game engine checks all the things in the game and moves them around, including checking if you pressed a button or opened a door. It does it so quickly that everything looks like it's happening at once, and so the game looks \"real.\"",
"In trying to keep with ELI5, a game engine is like a completely empty game, no levels, no characters, nothing.\n\nA game developer takes this empty game and adds the maps and characters to it to create a game you can actually play. \n\nSometimes developers create their own engine for just their games and sometimes developers buy someone else's engine to use. This saves a lot of time as you don't have to write everything again every time you create a new game, but does limit what you can do as only features (graphics, physics) that are in the engine from the start can be used (which is why new game engines are written often)",
"A game engine is to a programmer what prepackaged sauces are to a cook. If I want to make Spaghetti Bolognese I can buy a jar of sauce and some pasta and have a tasty meal in a short time or I can buy a bunch of ingredients and produce the sauce from scratch which takes a lot longer. \n \nIf you are willing and able to make your own sauce it will be tailored to your specific taste and needs, but takes much longer and requires more skill. Buying a jar is quicker and takes less cooking ability but you are limited to the flavour of the particular jar you bought. \n\n",
"I think you wanted to ask about \"[search engines](_URL_0_).\"",
"(bit late to the party but I'll try for a good 5-year old explanation)\n\nImagine you're in the world of dragons and knights. You're a powerful dragon on a great white horse with armor on. You see a menacing castle in the distance. While you look there the sky thunders. You ride to the castle.\n\nThis, so far, is what the game engine itself does - keep track what's where, what exists, how it looks and what state it is in.\n\nNow, make a drawing of how you see the castle, yourself, your horse and so on.\n\nThat's what a graphics engine does - just making a drawing of what it knows to exist from your point of view such that you can see what's going on.\n\nThink again of the dream world. Imagine you're riding on to the castle and you're just outside the gate.\n\nWhat you just did was what a physics engine usually does - moving the world forward in time according to the rules that are logical for that world.",
"Let's look at the word 'engine'. What is the first thing you think about when you read 'engine'? The first thing I think about is a car engine. What is a car engine? What do car engines do? \n\nA car engine is what makes cars go. Some cars have big engines that make the car go really fast. Other cars have smaller engines that use less gasoline. Some engines belong to big, fancy cars and some engines belong to small, cute cars. All cars have an engine, because the car engine is what makes cars move and all cars are built to move!\n\nA game engine is similar to a car engine, because the game engine is what makes games work! Now, let's think about what makes a game work:\n\nWhat kinds of video games do you like to play? When I was a kid, I liked playing a game called Super Mario Brothers. Have you ever played a Super Mario game? I think most people interested in games have!\n\nWhat kinds of things do you see on the screen when you play a Mario game? [Take a look at this picture.](_URL_0_) What do you see? I see Mario, a blue background, some green hills that Mario is standing on, some dinosaur enemies, a giant Bullet Bill, a Yoshi coin, and a bunch of letters and numbers at the top of the screen.\n\nHow does the game know how to draw those things?\n\nWell, before the game was made a bunch of artists got together and drew pictures of Mario, the dinosaurs, the Bullet Bill, the green hills, the blue background, and all the letters and numbers. The artists drew the pictures on a computer and saved the pictures in the game. The game engine knows where those pictures are saved and is able to take the pictures and put them on the screen.\n\nNow, imagine you are playing the Super Mario game in the picture and you want to jump on the dinosaur's head. What buttons would you press? You would probably hold the left button on the D-Pad and then press the A button. What does Mario do when you press those buttons? He runs to the left, jumps in the air, and lands on the dinosaur's head. How did the game know how to move Mario?\n\nThe game engine! The game engine can see what buttons you press on your controller. Based on the buttons you press, the game engine moves the picture of Mario around the screen. When you press left, the game engine makes the picture of Mario move left. When you press A, the game engine makes the picture of Mario jump up in the air.\n\nNow, what happens when Mario lands on the dinosaur's head? Is it different from what happens when Mario runs into the side of the dinosaur? Is that different from what happens when Mario runs into the side of the Yoshi coin?\n\nYes, they are all different! If Mario jumps on the dinosaur's head, the dinosaur is defeated. If Mario runs into the side of the dinosaur, Mario is defeated. If Mario runs into the side of the Yoshi coin, the coin is removed from the screen and the numbers at the top of the screen change. How does the game know what to do in each of these different situations?\n\nThe game engine! When the game was being built, the game makers decided how they wanted the game to act. Then, they gave the game engine a bunch of rules to let it know how to change the game when certain things happen. They also gave the game engine a way to know when pictures on the screen touch, called collision detection. Collision detection will tell the game engine when Mario touches a dinosaur or a Yoshi coin, and where the two pictures touched.\n\nIf collision detection tells the game engine that Mario touched a dinosaur picture on its head, the dinosaur is defeated and the game engine will take the dinosaur picture off the screen. If collision detection tells the game engine that Mario touched a dinosaur picture on its side, Mario is defeated and the game engine will restart the level. If collision detection tells the game engine that Mario touched a Yoshi coin, the game engine will take the coin picture off the screen and add a coin to Mario's collection.\n\nFinally, can you think of any games that are similar to Super Mario? When I was young, I also liked to play a game called Sonic the Hedgehog. Have you ever played a Sonic game? If so, do you think the people who made Sonic could have made the game faster if they had the Mario game engine? I think so!\n\nThe people who make video games realized this too, and started selling their game engines to other video game makers. This way, games can be made more quickly and easily. One popular game engine is the [Unreal Engine](_URL_1_) made by Epic Games. Here is a [list of all the games made on the Unreal Engine](_URL_3_). Most of those games were not made by Epic, but by other video game makers who paid Epic to use their Unreal Engine!\n\nThe idea of a game engine has become so popular that some companies are specializing in game engines without even making video games. One of these companies makes the [Unity game engine](_URL_2_) and is becoming very popular.\n\nThis way, a single company can make an engine and many people can make the games, just like a single company could make a car engine that is used in many different brands of cars!",
"A game engine in general is much like an automobile engine. Each device has differing parts all working harmoniously together under a specific set of rules, in order to achieve a main objective.\n\nEach part of an engine serves a specific purpose, and without that part the engine will not work properly. In games, there are various parts that are required for the game to work at all.\n\n* A game must be able to interact with a user in a meaningful way, this is the input/output section of the engine. It handles things such as key-presses, mouse clicks, taps on screen, etc. And, it also handles returning meaningful information back to the user about the key-presses, mouse clicks, taps on screen, etc.\n\n* A game must display some meaningful information about its state back to the user. This is normally the graphics portion of the engine. In the old days when things were simple this part of the engine was self contained, but still part of the overall game engine itself. Now this is rarely the case, most games now have a completely separate graphics engine which must be made to work with the main game engine. The graphics engine's whole purpose is to display things, period. Everything you see in a game is because of the graphics engine. It handles throwing up every single little dot on the screen.\n\n* Most people want to hear things, so this means some type of sound part is added to the engine. Very rarely do developers create their own sound code, it's far more normal to license this from another company which only does sound.\n\n* Game itself. This is where the fun parts come in. The game engine is after all, for a game right? This part of the engine does whatever numbers magic is necessary to pull off the actual game play. This means things like movement, collisions, placement and removal of objects, etc. This part is the make or break part. People are willing to forgive a lot, but being stuck within geometry of a game is not one of those things.\n\n* Physics. Most times this whole section is offloaded to another engine that deals specifically with the laws of physics. This portion sits between the output from the game engine and the graphics engine. The game gives the physics engine information about actions. The actions are then calculated by the physics engine, and the output is routed to the graphics engine for display to the user and back to the game engine for any additional processing. For example: if a player flips a coin in a game, the game engine computes what the action will be, heads or tails, determines if there are modifications to the coin flip such as how hard the flick was, and gives that information to the physics engine. The physics engine calculates flight paths, trajectories, momentum, and then hands off the outcome of the calculations to the display engine so it may draw the realistic looking coin toss on the screen.\n\nThere are many more pieces to a game engine. This is just a very simplistic look at how one may view it.",
"A game engine is nothing more than a bunch of code/software that handles the \"hard\" parts of making a game work so that the developers can focus on creating gameplay and content.\n\nSome things that a game engine may do:\n\n* Read and write graphics files (3D models, textures, sprites, etc.) and display them on the screen\n* Automate graphical special effects (animations, rotations, lens flare, etc.)\n* Track objects in the game world\n* Detect collision between objects\n* Provide information about frame rates, performance, and so on\n* Control maximum and minimum frame rates\n* Scale graphics to different screen sizes\n* Detect, report, and record input from keyboard, mouse, joystick, controller, mic, or other input device\n\nNot all game engines have the same features. However, they all provide ways that a programmer may interact with the features of the game engine, usually through code libraries containing functions, methods, classes, and event handlers.\n\nIs that clear enough or do I need to elaborate or clarify anything?",
"While EdgeOfDreams already made a pretty good post, its pretty techincal so for the real 5 year olds out there, its like choosing whether I want to play with Legos or Lincoln Logs. They don't provide prebuilt models of what you want to make and only provide a basis for you to expand on any idea you have. This way you dont have to make the building blocks and just start building :) Obviously this is pretty simplified but hope this helps less tech savvy people.",
"Imagine you're playing with dolls / action figures. Every second, you're moving their arms, heads, make sound effects, make them talk, and decide what's going to happen next. When you play, you're the game engine. \n\nThe same thing happens inside a video game -- the game engine knows how a gun sounds, what a car looks like and how it should move. A gazillion times every second, the game engine checks all the things in the game and moves them around, including checking if you pressed a button or opened a door. It does it so quickly that everything looks like it's happening at once, and so the game looks \"real.\"",
"In trying to keep with ELI5, a game engine is like a completely empty game, no levels, no characters, nothing.\n\nA game developer takes this empty game and adds the maps and characters to it to create a game you can actually play. \n\nSometimes developers create their own engine for just their games and sometimes developers buy someone else's engine to use. This saves a lot of time as you don't have to write everything again every time you create a new game, but does limit what you can do as only features (graphics, physics) that are in the engine from the start can be used (which is why new game engines are written often)",
"A game engine is to a programmer what prepackaged sauces are to a cook. If I want to make Spaghetti Bolognese I can buy a jar of sauce and some pasta and have a tasty meal in a short time or I can buy a bunch of ingredients and produce the sauce from scratch which takes a lot longer. \n \nIf you are willing and able to make your own sauce it will be tailored to your specific taste and needs, but takes much longer and requires more skill. Buying a jar is quicker and takes less cooking ability but you are limited to the flavour of the particular jar you bought. \n\n",
"I think you wanted to ask about \"[search engines](_URL_0_).\"",
"(bit late to the party but I'll try for a good 5-year old explanation)\n\nImagine you're in the world of dragons and knights. You're a powerful dragon on a great white horse with armor on. You see a menacing castle in the distance. While you look there the sky thunders. You ride to the castle.\n\nThis, so far, is what the game engine itself does - keep track what's where, what exists, how it looks and what state it is in.\n\nNow, make a drawing of how you see the castle, yourself, your horse and so on.\n\nThat's what a graphics engine does - just making a drawing of what it knows to exist from your point of view such that you can see what's going on.\n\nThink again of the dream world. Imagine you're riding on to the castle and you're just outside the gate.\n\nWhat you just did was what a physics engine usually does - moving the world forward in time according to the rules that are logical for that world.",
"Let's look at the word 'engine'. What is the first thing you think about when you read 'engine'? The first thing I think about is a car engine. What is a car engine? What do car engines do? \n\nA car engine is what makes cars go. Some cars have big engines that make the car go really fast. Other cars have smaller engines that use less gasoline. Some engines belong to big, fancy cars and some engines belong to small, cute cars. All cars have an engine, because the car engine is what makes cars move and all cars are built to move!\n\nA game engine is similar to a car engine, because the game engine is what makes games work! Now, let's think about what makes a game work:\n\nWhat kinds of video games do you like to play? When I was a kid, I liked playing a game called Super Mario Brothers. Have you ever played a Super Mario game? I think most people interested in games have!\n\nWhat kinds of things do you see on the screen when you play a Mario game? [Take a look at this picture.](_URL_0_) What do you see? I see Mario, a blue background, some green hills that Mario is standing on, some dinosaur enemies, a giant Bullet Bill, a Yoshi coin, and a bunch of letters and numbers at the top of the screen.\n\nHow does the game know how to draw those things?\n\nWell, before the game was made a bunch of artists got together and drew pictures of Mario, the dinosaurs, the Bullet Bill, the green hills, the blue background, and all the letters and numbers. The artists drew the pictures on a computer and saved the pictures in the game. The game engine knows where those pictures are saved and is able to take the pictures and put them on the screen.\n\nNow, imagine you are playing the Super Mario game in the picture and you want to jump on the dinosaur's head. What buttons would you press? You would probably hold the left button on the D-Pad and then press the A button. What does Mario do when you press those buttons? He runs to the left, jumps in the air, and lands on the dinosaur's head. How did the game know how to move Mario?\n\nThe game engine! The game engine can see what buttons you press on your controller. Based on the buttons you press, the game engine moves the picture of Mario around the screen. When you press left, the game engine makes the picture of Mario move left. When you press A, the game engine makes the picture of Mario jump up in the air.\n\nNow, what happens when Mario lands on the dinosaur's head? Is it different from what happens when Mario runs into the side of the dinosaur? Is that different from what happens when Mario runs into the side of the Yoshi coin?\n\nYes, they are all different! If Mario jumps on the dinosaur's head, the dinosaur is defeated. If Mario runs into the side of the dinosaur, Mario is defeated. If Mario runs into the side of the Yoshi coin, the coin is removed from the screen and the numbers at the top of the screen change. How does the game know what to do in each of these different situations?\n\nThe game engine! When the game was being built, the game makers decided how they wanted the game to act. Then, they gave the game engine a bunch of rules to let it know how to change the game when certain things happen. They also gave the game engine a way to know when pictures on the screen touch, called collision detection. Collision detection will tell the game engine when Mario touches a dinosaur or a Yoshi coin, and where the two pictures touched.\n\nIf collision detection tells the game engine that Mario touched a dinosaur picture on its head, the dinosaur is defeated and the game engine will take the dinosaur picture off the screen. If collision detection tells the game engine that Mario touched a dinosaur picture on its side, Mario is defeated and the game engine will restart the level. If collision detection tells the game engine that Mario touched a Yoshi coin, the game engine will take the coin picture off the screen and add a coin to Mario's collection.\n\nFinally, can you think of any games that are similar to Super Mario? When I was young, I also liked to play a game called Sonic the Hedgehog. Have you ever played a Sonic game? If so, do you think the people who made Sonic could have made the game faster if they had the Mario game engine? I think so!\n\nThe people who make video games realized this too, and started selling their game engines to other video game makers. This way, games can be made more quickly and easily. One popular game engine is the [Unreal Engine](_URL_1_) made by Epic Games. Here is a [list of all the games made on the Unreal Engine](_URL_3_). Most of those games were not made by Epic, but by other video game makers who paid Epic to use their Unreal Engine!\n\nThe idea of a game engine has become so popular that some companies are specializing in game engines without even making video games. One of these companies makes the [Unity game engine](_URL_2_) and is becoming very popular.\n\nThis way, a single company can make an engine and many people can make the games, just like a single company could make a car engine that is used in many different brands of cars!",
"A game engine in general is much like an automobile engine. Each device has differing parts all working harmoniously together under a specific set of rules, in order to achieve a main objective.\n\nEach part of an engine serves a specific purpose, and without that part the engine will not work properly. In games, there are various parts that are required for the game to work at all.\n\n* A game must be able to interact with a user in a meaningful way, this is the input/output section of the engine. It handles things such as key-presses, mouse clicks, taps on screen, etc. And, it also handles returning meaningful information back to the user about the key-presses, mouse clicks, taps on screen, etc.\n\n* A game must display some meaningful information about its state back to the user. This is normally the graphics portion of the engine. In the old days when things were simple this part of the engine was self contained, but still part of the overall game engine itself. Now this is rarely the case, most games now have a completely separate graphics engine which must be made to work with the main game engine. The graphics engine's whole purpose is to display things, period. Everything you see in a game is because of the graphics engine. It handles throwing up every single little dot on the screen.\n\n* Most people want to hear things, so this means some type of sound part is added to the engine. Very rarely do developers create their own sound code, it's far more normal to license this from another company which only does sound.\n\n* Game itself. This is where the fun parts come in. The game engine is after all, for a game right? This part of the engine does whatever numbers magic is necessary to pull off the actual game play. This means things like movement, collisions, placement and removal of objects, etc. This part is the make or break part. People are willing to forgive a lot, but being stuck within geometry of a game is not one of those things.\n\n* Physics. Most times this whole section is offloaded to another engine that deals specifically with the laws of physics. This portion sits between the output from the game engine and the graphics engine. The game gives the physics engine information about actions. The actions are then calculated by the physics engine, and the output is routed to the graphics engine for display to the user and back to the game engine for any additional processing. For example: if a player flips a coin in a game, the game engine computes what the action will be, heads or tails, determines if there are modifications to the coin flip such as how hard the flick was, and gives that information to the physics engine. The physics engine calculates flight paths, trajectories, momentum, and then hands off the outcome of the calculations to the display engine so it may draw the realistic looking coin toss on the screen.\n\nThere are many more pieces to a game engine. This is just a very simplistic look at how one may view it."
]
}
|
[] |
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[],
[],
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"http://i.imgur.com/I1t2N.gif",
"http://en.wikipedia.org/wiki/Unreal_Engine",
"http://unity3d.com/",
"http://en.wikipedia.org/wiki/List_of_Unreal_Engine_games"
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[],
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"http://en.wikipedia.org/wiki/Unreal_Engine",
"http://unity3d.com/",
"http://en.wikipedia.org/wiki/List_of_Unreal_Engine_games"
],
[]
] |
|
3pzxht
|
Why did Iberian colonization typically involve interbreeding with/integrating the natives, while British colonization typically involved displacing natives?
|
In South America and the Philippines, which were areas of Spanish/Portuguese colonization, the population is typically partially or fully native yet semi-integrated into Iberian culture (they are usually Catholic and usually speak Spanish/Portuguese).
In areas of British colonization such as New Zealand/Australia/US/Canada, the population is mostly of European descent.
Why is this? Is it entirely a result of higher population density in South America and the Philippines?
Was there less stigma on having children with the native people in Spanish colonies?
Was there some population phenomenon in Britain which meant that there were more women/families willing to move to the colonies? Were Iberian colonists mostly men, or were there large numbers of women/families who moves to the colonies as well? And if so, why did Iberian men marry native women more frequently than British colonists? Or is that assumption wrong, and British colonists frequently took native wives?
Were the British more brutal than the Iberians when it came to displacing native people?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/3pzxht/why_did_iberian_colonization_typically_involve/
|
{
"a_id": [
"cwb1yp1",
"cwbml78"
],
"score": [
2,
2
],
"text": [
"While someone else with deeper knowledge on this issue comes, I can answer one of your questions:\n\n > Was there less stigma on having children with the native people in Spanish colonies?\n\nWe have to distinguish between *actual* marriages between Spaniards and natives and other forms of producing mixed children (largely rape). In the case of actual marriages, they usually involved the natives who had converted, either by choice or force, to Catholicism. Those who had adopted Catholicism and Spanish culture were called *gente de razón* (\"people of reason\"), and those that had not were simply considered uncultured or simply savages, and of course they were stigmatised. \n\nIt is very important to clarify that these interracial marriages and especially the children that came out of it were certainly not stigma-free. The Spanish Empire developed a very complex racial classification system called [Casta](_URL_0_), which gave different categories to children born to parents of different races. You had different rights and could face more or less racism (which was very prevalent in the Spanish empire) depending on which category you were placed.\n\nThe Casta system is very complex and it includes all possible racial combinations, and you have to think of it as a racial pyramid, with the most privileged classes at the top. At the top obviously were the Spaniards themselves, divided into two categories: the peninsulars (born in Spain) and the criollos (born in the Americas to peninsular parents). Despite being racially European, criollos were excluded from high-level positions in the government, just for the fact of them being born in the Americas. So you can imagine that the lowest you get in the Casta system, the worse off you are. ",
" > Why is this? Is it entirely a result of higher population density in South America and the Philippines?\n\nNot to give the impression that this is a full, comprehensive answer to your question, but this is a very true statement. Populations of indigenous Americans were far higher in Central and South America than in what is now the United States and Canada. Pre-Columbian population estimates in Canada top out around 2 million... less than half of the lower end of population estimates for the Aztec empire alone, and that's just one of many cultural polities that existed in Central America at the time.\n\nThe places that you are thinking of as involving integrated populations likely had higher indigenous population density to begin with. Meanwhile, there are parts of Latin America where a particularly high percentage of the population is descended solely from Europeans, e.g. Argentina, which encompasses an area that was *comparatively* sparsely populated when Europeans arrived."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Casta"
],
[]
] |
|
9dcy4u
|
Why doesn't atoms nuclei collapse?
|
I'm not talking about the reason electrons don't crash into the atom nucleus.
The question I'm asking is, if the strong nuclear force is that much stronger than the electromagnetic force at the distances of a atom nucleus, why does it have a radius?
|
askscience
|
https://www.reddit.com/r/askscience/comments/9dcy4u/why_doesnt_atoms_nuclei_collapse/
|
{
"a_id": [
"e5gy921",
"e5h9r7j"
],
"score": [
23,
5
],
"text": [
" > The question I'm asking is, if the strong nuclear force is that much stronger than the electromagnetic force at the distances of a atom nucleus, why does it have a radius?\n\nIt's the same thing as will the atom. Nucleons occupy discrete orbitals within the nucleus.",
"At very short distances the strong interaction between nuclei gets repulsive. Not that it would be necessary: See the other reply, the nucleons have their orbitals. They are just more complicated than in an electron as the potential they see is created by these nucleons."
]
}
|
[] |
[] |
[
[],
[]
] |
|
6dx3u8
|
the restoring internet freedom act
|
What's in it? Intended consequences? Unintended consequences? Why do some senators argue it's good when most people seem to agree that it's bad?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6dx3u8/eli5_the_restoring_internet_freedom_act/
|
{
"a_id": [
"di61lkt"
],
"score": [
3
],
"text": [
"Restoring Internet Freedom Act. This bill nullifies the rule adopted by the Federal Communications Commission (FCC) on February 26, 2015, relating to the reclassification of broadband Internet access service as a telecommunications service.\n\n_URL_0_\n\n_URL_1_"
]
}
|
[] |
[] |
[
[
"https://www.congress.gov/bill/114th-congress/senate-bill/2602",
"https://www.bing.com/search?q=The+Restoring+Internet+Freedom+Act&qs=n&form=QBLH&sp=-1&pq=the+restoring+internet+freedom+act&sc=2-34&sk=&cvid=D7FF57CE442A4035AAFEE3F6BA99FE2E"
]
] |
|
78rk06
|
Can satellites be in geostationary orbit at places other than the equator? Assuming it was feasible, could you have a space elevator hovering above NYC?
|
'Feasible' meaning the necessary building materials, etc. were available, would the physics work? (I know very little about physics fwiw)
|
askscience
|
https://www.reddit.com/r/askscience/comments/78rk06/can_satellites_be_in_geostationary_orbit_at/
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"Geostationary orbits can only occur along the equator. Any orbit occurs on a two dimensional plane that passes through the center of mass for the object it is orbiting. For a satellite orbiting earth anywhere north or south of the equator the position directly below the satellite would have to move north and south with the satellites orbit, not geostationary. This also means that a space elevator could only work at the equator but there is a simpler reason that is easier to visualize. In theory, a space elevator would use centrifugal force to cancel out the force of gravity trying to pull the structure down. Anywhere outside of the equator the centrifugal force would not be in line with gravity causing a sideways force on the elevator. ",
"Short answer: no.\n\nLong answer: No, because an object in orbit does so by falling in a path with the center of the Earth in the center (if the path is a circle) or locus (if the path is an ellipse) of that path.\n\nYou could put a satellite in an orbit that crosses above New York City, but because the center of the Earth had to be at the center of the orbit, it would only be there once, or at most, twice a day. In order to have an orbit angled far enough north to reach New York, that same orbit world also have to be angled far enough south to reach Osorno, Chile at the other end. Angle the orbit a little farther so that it reaches Albany or even Montreal and you could have it cross over New York coming and going, but at the price of reaching Puerto Aisen, Chile on the south end.\n\nNeedless to say, no usable space elevator, theoretical or otherwise, could be built to whipsaw north and south every day like that.",
"It a satellite was at a distance from the planet so that it traveled around its orbit a the same rate that the planet turned, but had an orbital plane that was at an angle to the equator, the satellite would appear to travel north and south in the sky. You couldn't tether anything to it, unless that something also traveled north and south along the ground.",
"The answer is technically no. There are no \"geostationary\" orbits other than above the equator, because the circle drawn that's at a point at constant distance above a location on Earth that isn't on the equator doesn't qualify as an orbit.\n\nIn other words, you would have to be continuously expending fuel to stay on the circle drawn at a constant distance from a point on Earth that isn't at the equator.\n\nA sketch of the circle the object in space would have to follow:\n_URL_0_\n\nAs an aside, an orbit, specifically a closed orbit, is the equilibrium trajectory followed by an object where the lateral velocity is high enough that the gravitational pull of the central body isn't able to bring the object into contact with the central body.\n\nAgain, in simplified terms, the object would fall towards Earth, but it's moving sideways too fast, so it misses the ground and goes on its merry way, until it slows back down enough to fall towards Earth again, only to miss it again, and so on.",
"Hi! I work on the geostationary satellites for NOAA. Since you said you know very little about physics, here's a quick primer on orbits.\n\nOrbits occur when an object is falling sideways fast enough to \"miss\" the Earth. This might be hard to imagine, so imagine throwing a baseball. The baseball goes up and down, but moves sideways as well. The harder you throw it, the farther it goes. If you threw it hard enough (in a vacuum), it would miss the Earth and keep falling forever.\n\nNow, because gravity is exerted from the centers of mass (but the CoM of our satellite is relatively negligible), any orbit you travel in has to have the center of the Earth in its plane. This means you can't have a \"halo\" orbit over the North pole, or off to the sides of the Earth. In practical terms, we can say *any* orbit must cross the plane of the Equator at some point.\n\nSo, as this relates to your question. A \"geostationary\" orbit is a geosynchonous orbit (one full orbit is one Earth day) that is in line with the equator. Since this matches the Earth's rotation,, you're always over the same location. Now imagine tilting the orbit so it was inclined. You still orbit in one day, but you are moving North and South as you pass the Ascending Node and Descending Node (The points where you cross the equator). Thus, your ground track is a figure-eight pattern, with the neck centered on the Equator.\n\nSo, to answer the second part of your question, no, you couldn't have a space elevator over NYC. That would be in an orbit that doesn't cross the equator, which is not possible. Geostationary satellites (and, by extension, space elevators) are only possible at near-zero latitude.\n\nLet me know if you have any other questions!",
"You need to separate this into two different scenarios. The first is a satellite, the second is a space elevator.\n\nWith a satellite, there is only one force acting on the satellite: gravity. The consequences of this kind of system have been studied for centuries. Others have already given you the answer for that case, so I won't go into detail.\n\nWith a space elevator, there is another force acting on it: the tension in the wire. There are a lot of complicating factors, but for simplicity's sake, let's say that the wire is massless, infinitely strong, and perfectly rigid (all of those things are untrue of any real wire that would be used and present significant engineering challenges to building a space elevator) so that we can concentrate only on what happens at the end of top of the elevator. This extra tension will pull the elevator back towards the anchor point's latitude. The combined effect of gravity and tension will create a circular path no longer centered on the Earth's center of mass, but still centered on the Earth's axis of rotation. It will still be closer to the equator than the anchor point, but how far it is from the latitude of the anchor depends only on the length of the wire and the latitude of the anchor.",
"The only way to have a space elevator tethered away from the equator would be to have a *split* elevator cable, with one base north of the equator and the other one the same distance south of the equator. The cables would come together at or below GSO altitude and continue outwards to keep the center of mass of the combined system in GSO.\n\nYou could put one end near Albany, NY (42.6526° N, 73.7562° W) and the other end near Castro, Chile (42.4801° S, 73.7624° W). There's bound to be a corresponding set of suitable locations.",
"As a side note to the answers given I would like to point out some other interesting orbits. [Tundra orbits](_URL_0_) in particular are cool because you can get a similar effect to a geostationary orbit but with a higher apogee. They make a skewed figure 8 shape as the Earth rotates under it because of their high inclination. Sirius radio used these kind of orbits, By having three satellites in this kind of orbit trading places they hade a much higher apogee than geostationary orbits, allowing for a clearer signal. A variation of the Tundra orbit is the Molniya orbit. So even though it would not be possible to put a space elevator above NYC, you could put a constellation with an apogee right above it.",
"I think that you would ***really*** enjoy Issac Arthur's upward bound series, specifically his episode on space elevators found [here](_URL_0_) \n\nIf you like that then the entirety of his channel will keep you entertained for many hours like it did for me! Let me know if you end up watching it :)",
"Space elevators would make for one hell of a target for terrorist organizations. Let's say you're a Martian in the early Expanse setting and there's elevators tethered to New York and Chile. Blow up the elevator somewhere in the stratosphere and you've got a good chance of wiping out a few hundred million lazy Earthers.",
"Technically you can't have an unpowered halo or arbitrary geostationary orbit.\nAs a thought experiment - if you happened to have an absurdly generous fuel load and enough steerable impulse to push your mass around, you could set up a powered orbit pretty much anywhere.\nE.g. if you could generate enough impulse to balance the entire weight (not just mass...) of the ISS in a smooth way - that spread the force so the ISS wasn't ripped apart by the magic engines you've just invented - you could park it over the North Pole and keep it there.\nYou could also have \"powered hover\" orbits that balanced the \"falling and missing\" vector of normal orbits with a permanently applied powered displacement vector to keep satellites geostationary anywhere, at any altitude.\nThis is wildly impractical today, and may well always be wildly impractical.\nBut it could be possible with much more advanced technology - in theory, at least.",
"Ignore the people talking about a geostationary orbit for your second question -- a space elevator is no more in orbit than is your house; it is attached to the earth. A space elevator is akin to a rope with a weight at the end holding the rope up via centrifugal force. If you build this somewhere other than the equator, it would be a balance between gravity towards the center of the Earth and centrifugal force towards a place just as far from the equator as the anchor but much higher up. Such a space elevator would have weird curves (made worse if you try to climb it), and would not point even close to straight up, and would require far more/stronger material.\n\nYou could get a space elevator anchored in NYC, or you could get a space elevator *over* NYC, but not both.\n\nBasically, such a space elevator would be a weird, expensive abomination",
" > Can satellites be in geostationary orbit at places other than the equator?\n\nNot by just using gravity. This has been discussed extensively in the other answers.\n\nHowever, if you consider additional forces, then yes. These forces can either be natural (solar radiation pressure) or artificial (thrust). In the first case, we could use solar sails; in the second case, an electric thruster (or even a combination of the two). Either way, there is another force that adds up to gravity, therefore moving the position of the equilibrium point away from the classical \"geostationary\" (=equatorial, ~36,000 km altitude). The new equilibrium point can be displaced either radially (inwards or outwards) or out-of-plane (north or south).\n\nSources:\n\n[Displaced geostationary orbits using hybrid low-thrust propulsion](_URL_1_)\n\n[Light Levitated Geostationary Cylindrical Orbits are\nFeasible](_URL_0_)\n",
"Since I haven't seen it here yet, there is a concept for an [Orbital Ring](_URL_0_) that could work as you describe. The trick is that the inner part rotates to make a feasible orbit, and then the outer part stays still, allowing you to hover over areas normally not coverable by geostationary orbits.\n\n[This video](_URL_1_) goes into it in pretty easy-to-follow terms.",
"A geostationary orbit must be directly over the equator. Otherwise it will not be above the same position at all times (hence will not be geostationary). A geosynchronous orbit, however, can be at any orbital inclination. This would be an orbit that takes just over 24 hours to complete, causing it to track the same line in the sky each orbital period. You'd still watch it move through the sky each night, but if you stayed in the same place, you could observe it traversing the sky the same way every night. An orbit which is geostationary must also be geosynchronous, but a geosynchronous orbit may or may not be geostationary.\n\nNote that a geostationary orbit needs to be both directly above the equator and very round (the apoapsis and periapsis need to be nearly identical). Either of these being off will cause the satellite to slowly drift, oscillate in the sky, or both.\n\nAs others have mentioned, trying to create a satellite that hovers over NYC at all times would be very impractical, but theoretically possible with a constant force applied to constantly change its orbit.",
"Short answer: no. You could theoretically have a space elevator based in New York, but the cable wouldn't go straight up; it would be angled south towards the equator. If you tried to have a \"geostationary\" orbit anywhere not in the same plane as the equator, it would appear that the satellite was drifting north and south throughout the day.",
"To your first question: No, you can't have a Geostationary orbit anywhere except over the equator. But that is not a deal-killer for your second question.\n\nA space elevator could have a terminal in NYC in two situations:\n\n1. Putting a second terminal in the southern hemisphere and having both lines go up to the same point in GSO, and then a line out to your asteroid anchor form there.\n\n2. An Orbital Ring can be placed in any orbit you want. It has to go all the way around the earth, but you can have stationary terminals above anything that ring crosses over.\n\nOf the two, option 1 is simpler, but any space elevator going up to GSO required material we don't have yet. Option 2 can be built with current technology, and would be much more useful, but would be god-awful expensive.\n\nSomeone else mentioned Issac Arthur's youtube channel, specifically his Upward Bound series, and I will strongly second that."
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"https://pure.strath.ac.uk/portal/files/67305638/strathprints018865.pdf",
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2z1gyy
|
how do ocean creatures survive such great depths, 2500m plus while even our steel submarines are completely crushed?
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explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/2z1gyy/eli5_how_do_ocean_creatures_survive_such_great/
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"they are at that pressure through and through, while a sub is keeping an artificial pressure.",
"Because organic creatures (including humans) are mostly made of water, and water can't compress.\n\nSubmarines have a pressure hull which encloses an air-filled space. The strength required to resist the pressure at extreme deeps is extraordinarily high. But we have sent crewed vehicles to the bottom of the deepest ocean. It is possible to make a pressure hull that can withstand those forces."
]
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7op5xk
|
why do different items usually have the same shipping price even if they're completely different in size, weight, shape, etc?
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explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/7op5xk/eli5_why_do_different_items_usually_have_the_same/
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"Amazon takes a loss leader position when it comes to shipping. In basic terms, they take the hit on shipping in order to sell you and I more stuff.",
"One reason is that the shipping company has price ranges to simplify billing.\n\nA small box that weighs next to nothing costs the same to ship as a box sized exactly the same but containing four books.\n\nIf you look at the price ranges of shipping companies it usually says something like this:\n\nSize 1: not larger than AxBxC inches & not heavier than D ounce.\n\nAnd then they define size ranges. Your package costs as the first category it fits.\n\nThen, to simplify things further Amazon (or any other large retailer) goes I the shipping company and says “hey, we want to offer you the possibility of having five million packages of ours shipped yearly. We want them flat rate. Here is our statistics on the size and weight of all packages sent the last five years. What’s your offer?”\n",
"The money the vendor saves on simplicity and efficiency outweighs what they would make more accurate shipping rates.\n\nHaving dozens of shipping costs represents a lot of overhead. You have to weigh and or measure each time in its packaging, then do it again every time you combine packages. Then you have to pay someone to track it all, and correctly get that information to the shipper. It also makes for a worse customer experience, one of the reasons people shop at Amazon is they are sick of finding out at the last moment the $30 order the just put in will include $12.95 in shipping.\n\nInstead, you figure a number that represents an average and charge that for everyone. Maybe it is a little higher than average, and you pocket the difference. Maybe it is a little lower, and you adjust your prices to compensate. Then you get your shipper to make you a deal because it makes it easier for them as well...especially when you are paying by the truckload.\n\n",
"In addition to the legitimate reasons given by other users, I think a lot of it is just vendors moving cost out of the advertised price and into the shipping and handling charge. They just put as much as they can get away with, without it being related to the actual cost of shipping and handling. "
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5epdoo
|
Why doesn't Raoult's Law depend on the chemical nature of solute?
|
According to Raoult's Law, dissolving a solute into a solvent decreases the saturation vapor pressure. Being a colligative property, it doesn't matter what the chemical nature of the solute is, only how much there is.
However we know that things like melting point and saturation vapor pressure (and by extension boiling point) depend on the strength of intermolecular forces. We say that a compound with stronger intermolecular forces has a lower saturation vapor pressure (i.e., is less volatile).
**My Question:** If the solute being added to the solution causes there to be stronger intermolecular interactions, wouldn't this cause a lowering in saturation vapor pressure? If so, then the claim that Raoult's Law doesn't depend on the chemical nature of the solute is untrue.
Can someone help me untangle this?
---
**TLDR: If saturation vapor pressure is defined by strength of intermolecular forces, why does dissolving a solute into a solvent lower saturation vapor pressure regardless of its chemical properties when we know for a fact that different solutes have different strengths of intermolecular forces with the solvent?**
|
askscience
|
https://www.reddit.com/r/askscience/comments/5epdoo/why_doesnt_raoults_law_depend_on_the_chemical/
|
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"I think the issue here is it is not actually a \"Law\", it only holds in the case of weak interactions. [Real solutions can deviate from these laws.](_URL_0_)",
"Raoult's law is an approximation assuming an ideal solution and a non-volatile solute. This holds for very dilute systems.\n\nThe lowering of the vapour pressure of the solvent due to the presence of a solute can be visualised [here](_URL_0_). At the liquid surface, there are less solvent molecules available to be ejected into the gas phase and so, without invoking intermolecular forces at all, this would lead us to observe a lower gas phase pressure. \n\nMore thoroughly, the liquid-vapour equilibrium is shifted towards liquid because the rate of gas molecules condensing is larger. Once the rate of condensation lowers enough to equal the rate of evaporation, equilibrium is once again reached. However, the gas phase now has a lower concentration/ pressure compared to that above the pure solvent.\n\nDeviations in Raoult's law can be used to infer the strength of intermolecular forces between solute and solvent. A real life lower vapour pressure than that predicted by Rauolt's law would imply stronger intermolecular forces between the solute and solvent. So in this regard, your thinking is perfectly correct.\n\nEDIT: Spelling"
]
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|
83fk38
|
why is it that you hear about so many new amazing materials / inventions but you rarely see them being used or sold?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/83fk38/eli5_why_is_it_that_you_hear_about_so_many_new/
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"A lot of the time these inventions or new “breakthroughs” are sensationalized before they ever even get adequate testing. It’s not uncommon for articles to report on something and make it sound like it’s amazing when in reality scientists/organizations haven’t even tested the stuff enough to definitively say whether or not it’s actually useful/not dangerous/worth anyone’s time. These studies unfortunately often take a lot of time (years) because they must be thoroughly tested to make sure they are safe for the general public/whoever would be using them and to also make sure that they actually work well. \n\nEdit: So to sum it up, the product must be tested before it’s able to be put on the market for sale. ",
"You read about new inventions, *not* new products\n\nScientists may figure out how to make a battery with 100x the energy density of a current phone battery, but it required 5 years to make a battery the size of a nickle that costs $5M and is prone to exploding. That's not a commercially viable product even though it is a large improvement in energy density. No one is going to pay $50M to get a phone that is half the thickness, its just not a marketable product at that price point. After a few decades of work someone might figure out how to make it in a cost effective way or they may determine that its actually impossible, but after the initial report of the discovery nothing exciting happens for a while so you hear about it once but never again.\n\nThere are lots of awesome inventions and materials that can do anything *except leave the lab* because they're too expensive to implement on any reasonable scale.\n\nCarbon fiber took decades to find its way into consumer applications, it is now cheap enough to be used in a wide variety of things but it took a longgg time",
"two things really. One is people invent stuff that is \"neat!\" but don't no one really needs. THere is no real economic driver for it. It looks cool but doesn't solve a problem adequately for it to become popular or economically feasible.\nTHe second reason, is \"Hype\". Scientists invent and report on their research all of the time, but there is a long disconnect between what the research is and what it could become. This has to do more with media, marketing, and human psychology than anything else. Researchers will hype the value and use of their work so they can make a bigger impact on getting grant funding. News organizations pick up on 'interesting' potentially useful technology and report it as if it was really there or just a couple years away. THat is the disconnect. \nIf the researchers don't convince their funders that their work will eventually result in useful products (see reason 1 above), then they won't get funded. Media won't report on uninteresting research that has no chance for useful technology. And to help their readers, they have to describe 'what this weird research' can eventually result in.\n\nI write and review new technology grants all of the time. We don't fund things that have no eventual use or potential to solve some need even well into the future.\n\ntldr: Its all about the Benjamins.",
"Because you're hearing about things that are in laboratory testing, which is a LONG way from becoming a consumer product.\n\nHence the jokes about \"Graphene can do everything except make it out of the lab\"."
]
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4jeq8x
|
why does stroking (many times) my disposable razor over denim/jeans make it sharpen again?
|
It works, it is a tip I got from the internet, but how?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4jeq8x/eli5_why_does_stroking_many_times_my_disposable/
|
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"There are three possibilities:\n\n1) The effect is purely psychological.\n\n2) Rubbing it on your jeans is cleaning out little bits of hair, skin and soap that were clogging it.\n\n3) You are stropping it. \n\nIf a blade (either a razor or a knife) is made of good steel, then it will actually retain a sharp edge for quite some time. But because the metal is very thin near that edge, it will kind of \"fold over\" with use. Stropping or honing pushes the edge back into place. Barbers who use straight razors use a stiff leather strop, in the kitchen, you use a \"steel.\"\n\nYou should hone a decent kitchen knife every time before you use it, and it's important to understand that honing is ABSOLUTELY NOT sharpening. Sharpening actually grinds metal away, honing just pushes it back into place. Although this is Knife 101, a certain loudmouthed vulgarian TV chef [apparently does not know the difference between honing and sharpening.](_URL_0_)"
]
}
|
[] |
[] |
[
[
"https://www.youtube.com/watch?v=SBn1i9YqN1k"
]
] |
|
4y177b
|
why does a pitch that is slightly flat sound better than one that is slightly sharp?
|
What makes a flat sounding pitch more forgiving than a sharp sounding pitch. If one of my guitar strings is tuned slightly flat for example, it's not quite as harsh as one that is tuned sharply.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4y177b/eli5_why_does_a_pitch_that_is_slightly_flat_sound/
|
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"text": [
"I think that may be your opinion because flat sounds way worse to me than sharp. Can't say for sure though "
]
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|
774lu6
|
why is titanium flammable?
|
Specifically titanium shavings
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/774lu6/eli5_why_is_titanium_flammable/
|
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"The oxidation of titanium gives off heat. When the titanium heats up, this reaction proceeds faster and faster. This produces a fire, one that is quite difficult to stop. \n\nAs for why shavings and powder are flammable. It's the same reason why leaves are more flammable than a log. The oxidation reaction is limited by surface area. Making shavings from a block greatly increases the reaction speed. ",
"This is not really something special about titanium.\n\nMany materials have pretty much the same thing going on.\n\nMetals like titanium can oxidize. When that happens to iron we call it rust. With most metal objects they automatically form a thin layer of oxidized material on the surface. If you scratch that layer you expose the unoxidized metal which on contact with oxygen oxidizes.\n\nThe problem comes when the protective layer can not form quickly enough.\n\nIf you create lots of metal shavings you end up with a really big amount of surface area per mass of metal and all that surface area is exposed to oxygen in the air. A single spark under this circumstances can set it all aflame and lead to a small (or not so small) explosion.\n\nThis can also happen with materials that aren't metal but are at least somewhat flammable. Wood dust can explode too.\n\nA famous example of stuff becoming explosive when turned into powder/shavings/mist are grain silos which can explode in much the same way.",
"The reaction with oxygen is exothermic. Finer flakes/shavings have more surface area for the reaction to take place. At some point, it becomes a self sustaining fire.\n\nAnd I have seen it in action - we made titanium sponge where I used to work. Some fool tried to use a Dremel to cut around 2 kg of sponge off the electrode on which it formed.\n\nIt immediately caught fire - think of what magnesium burning looks like. It was that intense. They emptied two CO2 extinguishers on it, which only made it worse, so the idiot who started it tries to carry it outside - but it melted through the stainless steel tray he had it on (I still can't believe he could get near enough to pick it up, but he did)."
]
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65c5p2
|
why do hackers want to use linux os even though it's easier to use windows or mac os?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/65c5p2/eli5why_do_hackers_want_to_use_linux_os_even/
|
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"Once they get through the learning curve it is easier to use linux. Besides, linux is free. The other two will cost eventually. ",
"Linux is generally far more customisable and it's far easier to change things, test out ideas, etc. Also you're less likely to get viruses.",
"Windows/Mac are \"easier to use\" because a lot of time has been spent developing a software that makes decisions for the user, eliminating the level of knowledge a user needs in order to operate it. The cost to this is the user then has less direct control over what they can do with the system.\n\nPut me on a Linux system and I am a few keystrokes away from seeing all of the network traffic that is visible to my computer's network interface.\n\nOn a Windows system, I'm not even sure you can do that natively to the same degree, I'd probably have to download some special program and hope it does what I want it to do."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
a4km42
|
How did some ancient sites survive as tourist sites?
|
For example, the Romans used the Colosseum as an entertainment place. At which point did they decide to " You know what? We will just abandon this building and not demolish it so people hundreds of years from now could visit it as a tourist destination".
An how did pagan temples (Ancient Egyptian, Hellenic and so) survive? Until this day we see zealots destroying places of worship like how ISIS for example did with many ancient churches and Shia mosques. I doubt the Catholic church for example was more tolerant than people nowadays, or was it?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/a4km42/how_did_some_ancient_sites_survive_as_tourist/
|
{
"a_id": [
"ebhe5n4"
],
"score": [
2
],
"text": [
"Mostly because they were given another use. \n\nFor example, the pantheon in Rome was made into a Christian church and the Parthenon in Athens had various uses over the centuries, including as ammunition storage by the Ottoman Empire, which led to part of it exploding. \n\nThe Colloseum is an interesting one. It was left derelict for a very long time and I seem to remember it being filled with water at one point. The sculptor Cellini writing in the late 1500s describes it as a mystical place where people would go to summon the spirits of the dead. So it obviously had a special meaning to people.\n\n"
]
}
|
[] |
[] |
[
[]
] |
|
1bd47b
|
What was the largest migration in human history?
|
I had always thought that it would have been something like the major migrations which led to the fall (of the western half) of the Roman Empire. Something which keeps being talked about in that context is the Chinese pushing one group west which pushed another, etc, until you get the Huns and Goth, and Vandals pushed toward Roman lands. However, I have then read that the genetic evidence suggests that the people in Europe today are essentially the same people from up to 10,000 years ago, with mostly just changes in culture and language, rather than physical displacement of peoples.
If this is true, then all of these migrations were not really all that large and then my next guess for largest migration would be the millions of people who immigrated to the New World in the past 300 (and especially the last 150) years.
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1bd47b/what_was_the_largest_migration_in_human_history/
|
{
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"c95u5va",
"c95v08u",
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],
"score": [
4,
16,
4,
3
],
"text": [
"In terms of sheer numbers per year, Stalin's post-ww2 forced deportations and migrations of various eastern european populations have to be close to the top. Exact numbers are debated, but millions of people got shuttled around eastern europe in a few years time.",
"The [Partition of India](_URL_0_) in 1947 and the according migration of people to either Pakistan or India as the nations formed is likely the largest migration we have records for. About 12 million people moved.",
"The largest human migration was the period of Europe emigration between the Napoleonic Wars until the outbreak of ww2 (1815-1939) when about 60 million people left Europe for other areas of European settlement. ",
"It's not the largest, but it was big: [Great Migration (African American)](_URL_0_)\n\nThe Great Migration was the movement of 6 million African-Americans out of the rural Southern United States to the Northeast, Midwest, and West for most of the 20th century. (Source above)"
]
}
|
[] |
[] |
[
[],
[
"http://en.wikipedia.org/wiki/Partition_of_India"
],
[],
[
"https://en.wikipedia.org/wiki/Great_Migration_%28African_American%29"
]
] |
|
1um1eq
|
Are quarks really the smallest "form" of matter, or is that just the assumption since we can't effectively see what could be inside of them?
|
Also, are there any accepted theories out there stating that quarks are also made up of smaller pieces? Is it possible that there are simply no fundamental forms of matter? If that is possible, what would it imply? This stuff fascinates me and I'd greatly appreciate any insight.
|
askscience
|
http://www.reddit.com/r/askscience/comments/1um1eq/are_quarks_really_the_smallest_form_of_matter_or/
|
{
"a_id": [
"cejh2f3"
],
"score": [
27
],
"text": [
"Quarks are almost certainly indivisible, and here's why.\n\nThe uncertainty principle states that the product of the uncertainty in an objects position and in that objects momentum must be larger than a certain value. This has nothing to do with measurement, but rather with a fundamental property of the way frequency and magnitude relate - you can learn more by googling Fourier Transform or even just Uncertainty Principle.\n\nNow, experiments have shown that some types of quarks, if they have internal structure, are smaller than 10^(-18) meters - a thousand times smaller than a proton. This means that if there was some particles making up those quarks, those particles would have their position narrowed down to within 10^(-18) meters, and hence the uncertainty in their momentum must be very large indeed - so large, in fact, that the energy those particles would possess would be much larger than the mass of the quarks themselves. \n\nNow if there was a very large binding force, this could be overcome - but then we're talking about not just new particles, but new forces. \n\nIt's worth noting, I think, that in all modern string theories, particles taken as elementary in the standard model are represented by a single string.\n\n"
]
}
|
[] |
[] |
[
[]
] |
|
1xpn0i
|
Diphenhydramine(Benadryl) is most known as an allergy pill, but it's also a cough suppressant, anti-vomiting/nausea, sedative, local anesthetic, anti-OCD, etc. How does this work?
|
[Wikipedia says that Diphenhydramine](_URL_4_) is:
* An [antihistamine](_URL_7_) (inhibits histamine, used as an allergy treatment)
* An [anticholinergic](_URL_5_) (treats some symptoms dealing with smooth muscles in the GI tract, urinary tract, lungs, etc)
* An [antitussive](_URL_2_) (cough suppressant)
* An [antiemetic](_URL_8_) (treats vomiting, nausea, motion sickness)
* A sedative, used to induce sleep
* A local anesthetic
* An antagonist to [acetylcholine](_URL_1_), used to treat Parkinson's [extrapyramidal symptoms](_URL_3_)
It also lists claims that it [decreases OCD symptoms](_URL_4_#cite_note-11).
The [mechanism of action](_URL_0_) that Wikipedia lists several really different sounding things happening - it's a sodium channel blocker, interacts directly with histamine receptors, etc.
Did we just luck out that one of the first antihistamines we developed can do so many useful things, or is there some root cause behind all of these that fits together? I.e. is it a "generic blocker" that happens to be effective at several things we can handle being blocked but doesn't block anything that would be dangerous, or is it more complex than this?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1xpn0i/diphenhydraminebenadryl_is_most_known_as_an/
|
{
"a_id": [
"cfdjfg3",
"cfdpprp"
],
"score": [
2,
3
],
"text": [
"Just because a drug can be used to treat a condition doesn't mean that it does it well, nor does it mean that the adverse effects of the drug outweigh the benefit it may or may not produce. Broad, non-specific drugs tend to have a wide range of effects - intended or not. Sometimes a \"side effect\" of a drug when used for one condition turns out to be the treatment for another condition. These non-specific drugs were generally developed first, with more targeted, specific treatments coming later. ",
"I find this to be a fascinating area of medicine/pharmacology. [Antihistamines](_URL_0_) and [Phenothiazines](_URL_1_) are closely related families of medicines, please take a look at their similar chemical structure and related derivatives. It's no wonder that the effects are shared. take [Compazine](_URL_2_) and [Stelazine](_URL_3_) for example - only an organic chemist could easily differentiate these two molecules and their effects aren't terribly dissimilar either. They are however marketed quite differently. I agree with u/LostToApathy, first generation drugs do tend to exhibit more of a 'club like' rather than targeted effect. They may be old but they remain quite valuable in the treatment of disease. "
]
}
|
[] |
[
"https://en.wikipedia.org/wiki/Diphenhydramine#Mechanism_of_action",
"https://en.wikipedia.org/wiki/Acetylcholine",
"https://en.wikipedia.org/wiki/Antitussive",
"https://en.wikipedia.org/wiki/Extrapyramidal_symptoms",
"https://en.wikipedia.org/wiki/Diphenhydramine",
"https://en.wikipedia.org/wiki/Anticholinergic",
"https://en.wikipedia.org/wiki/Diphenhydramine#cite_note-11",
"https://en.wikipedia.org/wiki/Antihistamine",
"https://en.wikipedia.org/wiki/Antiemetic"
] |
[
[],
[
"http://en.wikipedia.org/wiki/H1_antagonist#First-generation_.28non-selective.2C_classical.29",
"http://en.wikipedia.org/wiki/Phenothiazine",
"http://en.wikipedia.org/wiki/Compazine",
"http://en.wikipedia.org/wiki/Stelazine"
]
] |
|
25i0mc
|
Can things spin in space with force coming from just one point?
|
My friends and I were arguing about this. If I had a flagpole in zero gravity, and I applied force moving perpendicularly to the pole to one end of it (as if a car ran into the base of the flagpole), would it spin about its center or would the whole pole just move in the same direction as the force?
Thanks, I just don't really understand the mechanics of spinning in space.
|
askscience
|
http://www.reddit.com/r/askscience/comments/25i0mc/can_things_spin_in_space_with_force_coming_from/
|
{
"a_id": [
"chhfx36"
],
"score": [
4
],
"text": [
"You're both right and both wrong. The resulting motion will be composed of a translation *and* a rotation. How much of each depends on the details. If you're comfortable with conservation of linear and angular momentum, you can approach it as a collision between some impactor and the end of the pole.\n\nIt could be that your friends are intuitively imagining a force *and* a torque being applied to the end. This would be the case if the end were clamped to whatever exerted the force, and that thing traveled strictly in a straight line. The clamp would exert a torque to counter that created by the applied force acting about the pole's centre of gravity."
]
}
|
[] |
[] |
[
[]
] |
|
1syra3
|
Were wild cats selectively bred by humans to give us our current day house cat?
|
I understand that over thousands of years genetic aberrations in wolves were selectively bred to give us our current day domesticated dogs, but was there a similar genetic modification through selection that was used on wildcats?
|
askscience
|
http://www.reddit.com/r/askscience/comments/1syra3/were_wild_cats_selectively_bred_by_humans_to_give/
|
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"text": [
"I suspect that dogs and cats were rather similar in their early domestication in that _neither_ was directly selectively bred by humans. It's thought that the wolf ancestors of dogs started following human groups around to basically scavenge kills and eat garbage. The friendliest, most human tolerant wolves got the most food and got killed by people least often, and over time you get dogs as a result. Similarly, but later on, people started growing and storing lots of grain from early agriculture. This attracts rodents and birds, and those attract wildcats. The wildcats best able to tolerate people hang around longer. The friendly ones are tolerated best (and at some point in both instances you can bet people are adopting the cute puppies and kittens). Eventually you get your basic cat.\n\nNow later on, for both dogs and cats people take the basic semi-feral animal and selectively breed for particular traits like color or certain behaviors. This with intentional mating of some animals to others. This has been done in both cats and dogs, but more in dogs because they have been specialized to accomplish so many jobs.",
"According to a podcast on how stuff works cats domesticated themselves and are the only animal to have done so. When people started farming grain they created a comfortable environment for cats, with barns to sleep in and plenty of mice and rats to eat. Because the cats were killing mice and rats people allowed them to stay and also made them comfortable, even doing things like taking care of them when they birthed kittens. When people shared agricultural knowledge and seeds and stuff, they would throw in some kittens too.",
"Yes. It was comparatively little compared to other domestic animals, but the domestic cat's genome was altered through human selection over centuries and it is different from its wild ancestor, the African wildcat. This is why we consider the house cat a domestic animal, jokes aside, and not a tamed one like the Asian elephant for example.\n\nThere are several breeds of cats that differ in their size, hair lenght and color, and even a couple with characteristic short tails (Manx) or that meow little (Chartreux). All this was achieved by selectively breeding cats over generations. Outside specific breeds, you can also tell apart your average feral house cat from a real wildcat by its smaller size and wider range of coat lenght and color - just as in any other animal that has gone through domestication.",
"Just be aware that purposeful selective breeding is a relatively \nrecent occurrence.\nThe process probably first started with a kind of natural selection for animals \nthat could 'get along' with humans.\nThose that did stayed. Those that didn't left.\n\nThere was some relatively recent work with wild foxes in Russia, \nwhere sel3ective breeding over only a few generations produced \none group of remarkably affectionate pet like foxes, \nand another of vicious unfriendly ones."
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
|
aagchp
|
Will the hydrophobic wooden ball sink?
|
If a wooden ball is covered with a hydrophobic coating and thrown into a water, a layer of air forms around it, it drowns (if it falls as through it was done in the air), or it remains on the water surface? Sorry for bad English.
|
askscience
|
https://www.reddit.com/r/askscience/comments/aagchp/will_the_hydrophobic_wooden_ball_sink/
|
{
"a_id": [
"ect2o7x"
],
"score": [
5
],
"text": [
"It will sink if it's denser than water, it will float otherwise, just as if it didn't have a hydrophobic coating. The buoyancy force on the ball depends on the amount of water displaced by the ball, and if that's higher than the gravitational force on the ball, it'll float. But the amount of water displaced doesn't change very much with a hydrophobic coating - it might slightly increase, but not by much."
]
}
|
[] |
[] |
[
[]
] |
|
jh5rh
|
If all movement is relative, is there a cosmic constant zero angular velocity?
|
I'm a layperson when it comes to physics, so bear with me. One of the things hammered into my head in physics class is that all motion is relative to whatever reference frame you happen to be using. But why, then, do we feel centrifugal force if we're spinning around an object, but not if that object is spinning and we're remaining still?
For example, if a spaceship tried to orbit the Earth at a high velocity, it would be flung away from the Earth. But if the ship stood still above the Earth and the Earth began to spin very quickly, the ship would simply fall toward the Earth.
Seen from the ship's reference frame, both of these events look the same, but have different outcomes. What causes this difference?
Thanks!
|
askscience
|
http://www.reddit.com/r/askscience/comments/jh5rh/if_all_movement_is_relative_is_there_a_cosmic/
|
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"text": [
"(Not a physicist) Because one thing is inertial motion, and another thing is *accelerated* motion. Inertial motion is completely reative to the frame of reference. Acceleration is *not* relative in the same way.",
"Velocity is relative, and there is no way to tell how fast you are moving. We cannot feel the motion of the planet even though we are flying through space at a very high speed.\n\nAcceleration, however, is not frame independent. That is to say, you will be able to tell if you are accelerating because you will feel a force acting on you. you can feel the force of acceleration when you slam on the gas pedal on your car. \n\nCircular motion requires acceleration. Think about the feeling you have when your car goes around a tight curve. Even though you might be going at the same speed, you can feel a force being acted on you.\n\nA body in motion will just keep going straight onwards if nothing acts on it. But, in your example, gravitational field pulls the spaceship around in a circle. The force of gravity acting on the spaceship keeps it in orbit, but only if the ship is moving at the right speed, as you noted.",
"As everyone else answered, in the Newtonian theory rotation is *not* an example of a uniform motion, and a rotating frame of reference does cause measurable effects (such as dizziness).\n\nNow, some people thought that it perhaps *should* be. The idea was that, when you're rotating, the galaxy—and the rest of the universe—rotated *with respect to you*, which causes the dizziness. This is (one sense of what is meant by) Mach's principle, which has spawned things like Brans-Dicke theory, & c. For a discussion see [gr-qc/9607009](_URL_0_). Nothing has been observationally confirmed, though.",
"(Not a physicist) Because one thing is inertial motion, and another thing is *accelerated* motion. Inertial motion is completely reative to the frame of reference. Acceleration is *not* relative in the same way.",
"Velocity is relative, and there is no way to tell how fast you are moving. We cannot feel the motion of the planet even though we are flying through space at a very high speed.\n\nAcceleration, however, is not frame independent. That is to say, you will be able to tell if you are accelerating because you will feel a force acting on you. you can feel the force of acceleration when you slam on the gas pedal on your car. \n\nCircular motion requires acceleration. Think about the feeling you have when your car goes around a tight curve. Even though you might be going at the same speed, you can feel a force being acted on you.\n\nA body in motion will just keep going straight onwards if nothing acts on it. But, in your example, gravitational field pulls the spaceship around in a circle. The force of gravity acting on the spaceship keeps it in orbit, but only if the ship is moving at the right speed, as you noted.",
"As everyone else answered, in the Newtonian theory rotation is *not* an example of a uniform motion, and a rotating frame of reference does cause measurable effects (such as dizziness).\n\nNow, some people thought that it perhaps *should* be. The idea was that, when you're rotating, the galaxy—and the rest of the universe—rotated *with respect to you*, which causes the dizziness. This is (one sense of what is meant by) Mach's principle, which has spawned things like Brans-Dicke theory, & c. For a discussion see [gr-qc/9607009](_URL_0_). Nothing has been observationally confirmed, though."
]
}
|
[] |
[] |
[
[],
[],
[
"http://arxiv.org/abs/gr-qc/9607009"
],
[],
[],
[
"http://arxiv.org/abs/gr-qc/9607009"
]
] |
|
84enec
|
Is it true US, French and British forces fought in the Russian civil war?
|
I’ve read they their troops to help the tsar, how much truth is there to this?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/84enec/is_it_true_us_french_and_british_forces_fought_in/
|
{
"a_id": [
"dvpdi2o"
],
"score": [
4
],
"text": [
"Please check out my earlier answer on this topic. There is always more to be said though, so feel free to ask if there's anything it does not cover. But in general I will mention that they did not send troops to send the Tsar (who had long since been toppled), but to restore an Eastern Front against the Germans. \n\n[This answer explains the motivations and gives an overview of the Allied Intervention, and also discusses the French participation more specifically.](_URL_1_)\n\n[This one looks specifically at America's role in the civil war.](_URL_0_)"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/6y7qtx/why_did_the_us_send_troops_into_russia_during_the/",
"https://www.reddit.com/r/AskHistorians/comments/7rz6k0/how_come_the_reds_won_the_russian_civil_war_while/_"
]
] |
|
9lbvpy
|
why does one full rotation equal 360°?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9lbvpy/eli5_why_does_one_full_rotation_equal_360/
|
{
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"text": [
"The metric system recommends using radians and not degrees. The math always works much better in radians. You can seamlessly switch back and forth between exponential, power-series and trigonometric functions (sine, cosine, etc) when you use radians.\n\nWhy degrees ended up being 360 is a historical (pre-historical?) quirk. There are 360 days in a year. Multiples of 12 and 60 were common in ancient systems because they have a lot of divisors.",
"Because it was made by a civilization that existed before the metric system. It came up around the time a ancient Greece and Babylon, so most ideas around why it's 360 is more educated guesses that proof.\n\nFor starters we know that the Babylonians and Persians had a calendar based off of a 360 day period so that seems reasonable to tie it to a circle if the said circle was used as a calendar. \n\n\nThe Babylonians also used a base 60 counting system, which doesn't fit into 100 very nicely. \n\nAlso 360 is just such a nice number for math. It has a ton of divisors, many more than 100 does, which makes doing fractions of a circle much easier to calculate when your TI-84 runs out of batteries. ",
"360 is a relic of ancient base 12 mathematics from the middle east.\n\nThe Mesopotamians were big fans of 12 and its multiples because of how simple the mathematics are.\n\n360 is evenly divisible by: 180, 120, 90, 60, 45, 40, 30, 24, 20, 18, 15, 12, 10, 9, 8, 6, 5, 4, 3, and 2.\n\nIt has a *huge* number of clean divisions.\n\n100 is way less functional. 50, 25, 20, 10, 5, 4, 2."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
ah1vn1
|
mood swings due to hormones (like contraception or pms)
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/ah1vn1/eli5_mood_swings_due_to_hormones_like/
|
{
"a_id": [
"eeartii",
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],
"score": [
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2
],
"text": [
"Hormones produced by the ovaries act as powerful neurotransmitters. When the amount you have in the body changes, it can affect your mood because it affects your brain.",
".\n\nhormones are signaling things, ant they effect almost the whole body including neural, mental,and emotional stuff. some people find it affects that aspect for them particularly strongly. "
]
}
|
[] |
[] |
[
[],
[]
] |
||
5kains
|
Why does hair loss always begin from the top region of the head?
|
Why does pattern hair loss in men particularly seems to always start from the same region, top of the head, and never from the sides?
|
askscience
|
https://www.reddit.com/r/askscience/comments/5kains/why_does_hair_loss_always_begin_from_the_top/
|
{
"a_id": [
"dbn15dc"
],
"score": [
3
],
"text": [
"I answered a very similar question a few days ago:\n_URL_0_\n\nIt has to do with varying levels of DHT sensitivity in different follicles of the scalp. Also, some men begin with the balding starting at the temples, which is how receding hairlines begin."
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/askscience/comments/5j3klc/why_do_bald_men_and_perhaps_women_maintain_a_ring/?st=IX5TMPM7&sh=405317a6"
]
] |
|
21bypx
|
In the Middle Ages, where there any roguish adventurer-types like movies and games?
|
You all know the type. The hardy traveler with nothing but a sword at his side and the clothes on his back, wandering the world in search of adventure, battling evil-doers with his trusty steed. Now while I assume it's safe to say that there weren't many fair maidens being rescued from tall towers or dragons being slain, were there fellows like the commonly portrayed adventurer/ranger type of hero often seen in games and movies?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/21bypx/in_the_middle_ages_where_there_any_roguish/
|
{
"a_id": [
"cgbq9pq"
],
"score": [
4
],
"text": [
"The idea of these types of heroes certainly existed by the 1600s, since Don Quixote was written (in 1605) to mock the chivalric novels that were popular at that time. In a way, Odysseus is also the same type of character, albeit travelling on a ship with a crew not alone on a horse. This doesn't answer the question, but it shows this type of character has a very long history in popular culture. I'm sure someone can expand more on this."
]
}
|
[] |
[] |
[
[]
] |
|
smk6y
|
why small smudges/scratches wreak havoc on audio cd's, but don't seem to affect data and game cd's.
|
it seems logical to me that a smudge should be able to halt a game install for example, but rarely ever does.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/smk6y/eli5_why_small_smudgesscratches_wreak_havoc_on/
|
{
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85,
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"text": [
"As a follow-up question, why can a CD that's stratched to shit and unable to play on any CD player be imported at perfect quality onto my PC / console?",
"part of it is audio cd can detect, but not correct, read errors. data cd employs redundancy and can actually correct a certain amount of read errors. audio cd uses 2352 (i think, it's been a while) byte sectors, while data cd uses 2048 byte sectors- but in reality, both are actually the same size sectors, the difference is that redundancy. the reason behind it- audio doesn't have to be reproduced *exactly*, if there are a couple read errors, some samples are discarded and replaced with interpolation, and it happens so quickly you most likely won't notice it. data cd needs to be more resilient, hence the redundancy. now in the case of a *lot* of read errors, the audio cd will start skipping, that has more to do with not being able to lock on to the \"groove\" for lack of a better word (showing my age?). the data cd will just fail- but you might get lucky and that missing data might be part of a rarely used file.\n\n\\*edit\\* - so i'm wrong about audio cds not doing error correction, they do have some- but data has more redundancy, so can correct more errors, so the gist of what i said is still (mostly) correct.",
"Like you're five:\n\nTo protect from scratches, only around 70% of your CDs actually contain data. The other 30% is [extra info that's there to help reconstruct data](_URL_0_) that can't be read.\n\nData CDs have even more of these extra info than audio CDs.\n\nThe makers of CDs figured that if parts of an audio CD can't be read, your CD player can just \"guess\" what's in there by looking at the music that's *before* and *after* the broken part, so it needs less error correction than data CDs.\n\n\n",
"a lot of it has to do with the quality of the error correction the disk drive is capable of. [this video](_URL_0_) explains the error correction process in an interesting way. it's all to do with the number 11",
"LY5:\n\nAn audio CD is like a book, with all the words written on the pages in the order it needs to be read.\n\nBut, a data CD is like a book with copies of pages in random places in the book.\n\nWhen the CD gets scratched, it's like drawing on, or ripping out some of the pages. It doesn't matter if a data CD is damaged, since it probably has copies of the damaged pages, but an audio CD doesn't have copies, so that's why it's more damaging for them."
]
}
|
[] |
[] |
[
[],
[],
[
"http://en.wikipedia.org/wiki/Cross-interleaved_Reed-Solomon_coding"
],
[
"http://www.youtube.com/watch?v=sPFWfAxIiwg"
],
[]
] |
|
4pfvdo
|
Has the increased workforce participation of women reduced wages?
|
Since the 1960s, the percentage of women who work has increased, increasing the size of the workforce. Has this reduced wages?
The only thing I have been able to find on the internet is in /r/theredpill so it's not an unbiased source.
|
askscience
|
https://www.reddit.com/r/askscience/comments/4pfvdo/has_the_increased_workforce_participation_of/
|
{
"a_id": [
"d4l9ca8"
],
"score": [
6
],
"text": [
"It certainly doesn't appear that way. [Here](_URL_1_) is the real median personal income, which has been rising since the 1980s, as has [the humber of dual income householda] (_URL_4_) and the % of [the workforce made up of women](_URL_3_). Furthermore, [mens wages do not appear to drop when women's wages rise](_URL_2_). The economy is not a zero sum game, see [lump labor fallacy](_URL_0_). "
]
}
|
[] |
[] |
[
[
"https://en.m.wikipedia.org/wiki/Lump_of_labour_fallacy",
"https://fred.stlouisfed.org/series/MEPAINUSA672N",
"http://4.bp.blogspot.com/-JlRZTNjlbGs/UMFdMBgMgpI/AAAAAAAAG_I/VbEA9h2QJCI/s1600/a1-us-individuals-real-median-income-by-sex-with-recessions-1947-2010.png",
"https://www.dol.gov/wb/stats/Civilian_labor_force_sex_70_12_txt.htm",
"http://www.pewresearch.org/ft_dual-income-households-1960-2012-2/"
]
] |
|
38m2l7
|
Why does the label on my MSG say it has 0% protein?
|
I understand that glutamic acid is not technically a protein since it's a single amino acid, but from a nutritional standpoint, shouldn't that not matter?
|
askscience
|
http://www.reddit.com/r/askscience/comments/38m2l7/why_does_the_label_on_my_msg_say_it_has_0_protein/
|
{
"a_id": [
"crw1wgs"
],
"score": [
12
],
"text": [
"Nutrition labels are mandated by law. Like when you buy a bottled water, the nutrition label tells you that it has 0% everything. The deinition of what's protein and what's not is determined by the FDA (in America). \n\n_URL_0_"
]
}
|
[] |
[] |
[
[
"http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocumentsRegulatoryInformation/LabelingNutrition/ucm2006828.htm"
]
] |
|
3ibn42
|
When a material is cut or broken, where exactly is the separation happening?
|
Does the break happen at a molecular level or is it at a larger scale? I know the atoms aren't spring but do molecules break apart?
|
askscience
|
http://www.reddit.com/r/askscience/comments/3ibn42/when_a_material_is_cut_or_broken_where_exactly_is/
|
{
"a_id": [
"cuf0i53",
"cuf1c9q"
],
"score": [
20,
5
],
"text": [
"Depends on material:\n\n\nWhen you break ice, you break the Van der waals bonds between molecules.\n\n\nWhen you break a metal, the metal is all atoms bound by metalic bonds so you break metal to metal bonds.\n\n\nIn some ceramics, the ceramic can be thought of one big molecule, and you are breaking molecules. (Ionic and covalent bonds)\n\n\nIn some you can be breaking between molecule thick plates.\n\n\nIn polymers, you can think of a polymer like a sphagetti. Each individual strand is strong but connections between them are weak. You are most likely pulling apart the strands, not breaking them. However some may have very long strands or interconnected ones. In those cases you are breaking the molecular bonds.\n\n\nIn all cases the crack is likely to follow flaws in the material (or weak points).",
"In the case of metals, most metals form crystalline structures when the material solidifies from a molten state. The crystals grow into grains, areas where the crystalline molecular structure are all aligned, but since multiple crystals begin to grow in different areas, there are grain boundaries between adjacent crystals. This is where metals typically fracture. This is also why heat treating, forging, and other processes are used - to increase the order of the grain structure.\n\nIn woods, it's between fibers - sort of analogous to metal, but the structure is formed as the plant grows.\n\nPlastics are very different at the molecular level than the previous two materials. In polymers, there are long chains of molecules. A thermoset is similar, but there is more cross-linking between the chains. I'm less familiar with plastics, but I believe they still can grow into crystals, in which case failure as as described above, or they can be more uniformly arranged, and then fracture involves pulling the long chains away from one another, or separating the cross-linked bonds in a thermoplastic."
]
}
|
[] |
[] |
[
[],
[]
] |
|
365u14
|
Is the influence of the Roman Empire overstated in Western culture when compared to other ancient civilizations like the Chinese or the Persians?
|
I know Rome is seen as the first time the West really rose to prominence and it has much to do with the current culture, but I am thinking in global terms here. When compared to other great empires how do they really measure up?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/365u14/is_the_influence_of_the_roman_empire_overstated/
|
{
"a_id": [
"crb1jui",
"crb4x80"
],
"score": [
7,
5
],
"text": [
"Influence on what, exactly? It's hard deny its influence on European civilization, if anything because of thr sheer amount later people intentionally identifiyng with the Greco-Roman tradition. Any influence on a larger scale is terribly hard to quantify or compare.",
"I don't think it is overstated, the Roman Empire had an enormous impact on so many aspects of the various civilizations that came after it, everything from language, art, law, commerce, governance, engineering, religion, warfare, architecture the list goes on. It would take several books to recount all the ways Rome influenced the world that came after so let me briefly focus on one. \nThe reason Mosques have domes is because in about 126AD the Emperor Hadrian re-built the temple to all the gods and crowned it with the largest unsupported dome ever built, five hundred years before Muhammad was born. The temple Hadrian built is of course the Pantheon which still stands in Rome. The Pantheon was the grandest and most important religious building in Rome after it was built, it's dome was and still is an engineering and architectural marvel.\nFast forward to to the year 532, the capital of the Empire has moved from Rome to Constantinople the religion has changed from pagan to Christian and another emperor wants to build (or re-build) the most important religious building of his day. The Emperor was Justinian and the building he erected was the Hagia Sophia. To crown his building he decided to harken back to the pantheon only on a larger more impressive scale. The Haglia Sophia's and its dome went on to influence other churches in the byzantine empire like Kathisma in Bethlehem. starting in the 7th century the Byzantine Empire began it's slow decline, Islamic conquerors began to chip away at Byzantine territory and in the process converted many christian churches to Mosqes, they were particularly impressed with the Byzantine domes and used them as a blue print for their most important Religious buildings like the dome of the Rock on the site of the old temple mount in Jerusalem. When the Byzantine Empire finally fell to the Ottomans in 1453 they converted Hagia Sophia into a mosque and it again influenced the construction of other Mosques and religious building in the Islamic world. Even the Taj Ma Hal in India can trace its architectural lineage back to Hadrian's pantheon.\nAgain this is a very brief explanation and the overall shape and construction of domes changed a lot in that time but it dose not negate the fact that the decision of a Pagan Roman emperor to build his most important religious structure with a dome had a direct influence on the religious buildings of a culture that we might not at face value think have anything at all in common with the likes of Jupiter, Mars, and Venus. "
]
}
|
[] |
[] |
[
[],
[]
] |
|
ix2m6
|
My bottle of bleach claims to kill 99.9% of all household germs.
|
My bottle of bleach claims to kill 99.9% of all household germs. What is the .1% of germs that are not killed with bleach?
|
askscience
|
http://www.reddit.com/r/askscience/comments/ix2m6/my_bottle_of_bleach_claims_to_kill_999_of_all/
|
{
"a_id": [
"c27bnto",
"c27bztf"
],
"score": [
2,
5
],
"text": [
"It's probably a marketing thing. If they said \"Kills 100% of all household germs\" and someone ran tests and found just one germ cell alive, the bleach manufacturer could be sued into oblivion. \n\nThe '99.9%' gives them an 'out'.",
"What kind of bleach is it? [Clorox regular bleach](_URL_0_), for one example, is a registered disinfectant. Based on the US EPA [website](_URL_1_) disinfectants are \"used on hard inanimate surfaces and objects to destroy or irreversibly inactivate infectious fungi and bacteria but not necessarily their spores.\" I'm not sure what time frame or concentrations are required for this definition, but I did find one article that looked at the effectiveness of 10% bleach on the spores of Bacillus anthracis, the causitive agent of anthrax. The [article](_URL_2_) clearly demonstrated that anthrax spores can be killed by bleach, however if the spores are at a very high concentration, or if they are exposed to bleach for too little time (30 minutes at high concentrations) some can survive. So if there is a lower cut off for time of exposure required to kill a spore, Bacillus anthracis spores could be one example of that 0.1% of germs that could survive."
]
}
|
[] |
[] |
[
[],
[
"http://www.clorox.com/products/clorox-regular-bleach/faq/",
"http://www.epa.gov/oppad001/ad_info.htm",
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957119/"
]
] |
|
9t0bpx
|
how does one navigate buying an engagement ring with so many industry pitfalls?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/9t0bpx/eli5_how_does_one_navigate_buying_an_engagement/
|
{
"a_id": [
"e8soluj",
"e8sqxci",
"e8srdg1"
],
"score": [
20,
2,
2
],
"text": [
"I found a jeweler that was referred to me that wasn’t a national brand. They spent time teaching me about diamonds and how they’re graded and what you can expect for the price you’re paying. \n\nI ended up buying a loose diamond from them after they let me look at a bunch of stones, and then they put it in a setting for me. \n\nIt was much cheaper than buying a “pre-made” ring, and I was able to get a fantastic stone too. \n\nI would recommend checking around for an independent jeweler. It seems like they’re more willing to help you learn before you buy. ",
"The way to not get ripped off is to do your research. I went through about 2 months worth of work when I bought my (now) wife's ring but spent a 3rd of what it was appraised at.\n\nWe went to about 20 different stores to find the style of ring she liked, the cut of diamond she preferred, the size of stone that looked good on her hand vs our budget, etc.\n\nAfter that I searched online to find exactly what I wanted and what vendors supplied what I was looking for. I contacted the manufacturers and got a list of local vendors that carried their product. Had to special order the ring as no one stocked it, but that wasn't much of an issue.\n\nThen I worked with some local suppliers to find a loose stone in the weight and cut I wanted and then looked at about 15 samples before I found a stone I was happy with for the price.\n\nBasically, the places you can \"save\" money on an engagement ring are:\n\n* The metal the ring is made of. Platinum is stupid expensive, but looks almost identical to properly maintained white gold. You can even get away with silver if your future partner isn't a stickler for tradition\n\n* Moissanite looks identical to diamonds and is significantly cheaper. If your SO is ok with it, it's a huge budget saver. Don't lie and say it's a diamond if it isn't. They'll find out.\n\n* Non-Certified Diamonds. These are basically diamonds, usually from Russia or China, that don't follow the strict certification process that other diamonds go through. It means there's a chance that they're conflict diamonds, or not mined ethically, or from some other source but, if you're ok with the potential ethical risk, they're cheaper (20-30% I found) than similar cut and clarity diamonds that are certified. Another option is Artisan Diamonds (man made diamonds). You can usually get a synthetic diamond for cheaper than a similar natural diamond\n\n* Know what you want and that there are options. Many jewelers just buy their merchandise from vendors that actually make it. Usually that means multiple shops will carry the same lines of product and can usually order anything from the vendors catalogue. There are also usually two or three vendors that sell identical or nearly identical pieces, which usually means you can find a lower price than what you've initially seen (often you're paying extra for the brand recognition)\n\n* Learn a bit about how stones are graded and priced, that gives you a good idea of where you can skimp, and to what extent. My wife's ring has a sever visual occlusion which made it much cheaper than it's cut, colour, and weight should have meant. The defect is in the cut at the bezel (where the stone mounts to the ring). You'll never see it when the stone's set and it doesn't detract from the brightness of the stone and you'd be very hard pressed to pick it out with a loupe unless you're looking for it.\n\n* Find a Gold Smith. They often do commission work if you want something very specific and will charge much less than jewelry stores for the same work.\n\nThere are a lot of other options out there too, happy to answer other questions.",
"As a voice counter to the \"engagement rings are stupid and a waste of money never buy one\".\n\nI love my ring. It's my favorite possession in the whole world. I wear it 75 percent of the time and get complements all the time about it. I'm excited about it one day being a family heirloom my kids are excited to own. My kids can't inherit my vacation to Rome and it's not like I live in a place where homeownership makes sense (why would I take on the tax burden and maintnance burden when I could rent the same space for less money and pocket the difference), so if you want a ring buy the frekin ring. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
13m617
|
Why do we care so much about the facial structures of our mates?
|
From an evolutionary standpoint, why do we see some faces as pleasant looking and want to be with those people?
|
askscience
|
http://www.reddit.com/r/askscience/comments/13m617/why_do_we_care_so_much_about_the_facial/
|
{
"a_id": [
"c755k06",
"c756yz5",
"c75748r"
],
"score": [
39,
20,
6
],
"text": [
"To make it clearer, I think what the OP is trying to say is that facial features don't seem to provide any obvious evolutionary advantages, unlike the rest of our body. So we're selecting for an arbitrary set facial features for no apparent reason.\n\nEdit: So apparently I'm both ugly and ignorant, as shown below.",
"Facial symmetry affects our perception of the healthiness of other individuals.\n\nThere are some studies that hypothesize that it predicts freedom from disease/ability to cope with illness etc. \n\nThere's a few papers on it mentioned on the wikipedia [facial symmetry](_URL_0_) page. \n\nA quick search on google scholar turned up this paper : _URL_2_ in which perceived facial attractiveness predicted longevity. \n\nEvolutionary psychologists would say that several facial features pertain to different aspects of health. [This](_URL_1_) paper seems to summarise some of the work on it. It's behind a paywall but I can get at it later on if someone would like it summarised and can't access it themselves.\n\nSince it's not really something you can manipulate in an experiment: you can only test people who are rated facially attractive or not for various evolutionary advantages and make inferences, which makes it something thats difficult to be fundamentally scientific about.",
"So far, three factors have been mostly noted in literature regarding the attractiveness of faces: symmetry, averageness and sexual dimorphism (pronouncedness of facial features that develop during puberty as a result of sex hormones).\n\nThe theoretical approach mostly assumed in this research is that of evolutionary psychology - unsurprisingly, given we're talking about something that's directly related to reproduction. \n\nThe explanation usually given for our attraction to average, symmetrical faces is the apparent lack of illness - increasing the chances that offspring come out healthy as well. \n\nThe explanation for a preference for sexual dimorphism (manly features on men, such as a strong jaw and a deep brow and feminine features on women such as a rounded face and smooth skin) is thought to lie in stereotypical behaviours and bodily features associated with the same sex hormones that trigger these facial changes in puberty: muscles on men, child-bearing hips on women for example. Because although no longer as much the case in today's society, a succesful tribe back at the dawn of man relied on strong men and fertile women.\n\nHope I helped!"
]
}
|
[] |
[] |
[
[],
[
"http://en.wikipedia.org/wiki/Facial_symmetry",
"http://cdp.sagepub.com/content/11/5/154.short",
"http://www.ehbonline.org/article/S1090-5138(03)00036-9/abstract"
],
[]
] |
|
5ql46v
|
how exactly do the different settings on dryers (i.e. "permanent press") affect clothes?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/5ql46v/eli5_how_exactly_do_the_different_settings_on/
|
{
"a_id": [
"dd0bauq",
"dd0dgoi",
"dd0hlqw"
],
"score": [
22,
6,
40
],
"text": [
"The heat output is anything from very hot air (whites) to completely unheated air (air dry). Certain fabrics will shrink with too much heat, and colors will fade. ",
"Lower heat and slower tumble. At least on my dryer. I use it on most clothes with exception to whites, sheets, blankets,and towels. ",
"According to [Sears](_URL_0_):\n\n > A washer on permanent press will wash clothes in warm water and rinse them in cool water, maintaining a mild agitation and spin. The warm water helps relax creases while the slow spin prevents new wrinkles from forming. A permanent press cycle is gentler than a regular cycle, making it good for synthetic fibers like polyester, rayon and knits. Because it does not use hot water, a permanent press cycle will also reduce shrinking and color fading.\n\n > A dryer on permanent press uses medium heat to smooth out wrinkles as it dries, while avoiding the high heat that can shrink clothes and fade colors."
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.sears.com/articles/appliances/washers-dryers/what-is-the-permanent-press-cycle-on-a-washer-or-dryer.html"
]
] |
||
a7lrpq
|
why is thermal clothing warm?
|
Is the fabric different from other clothes? Or is it the way it is made?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/a7lrpq/eli5_why_is_thermal_clothing_warm/
|
{
"a_id": [
"ec3yj7x"
],
"score": [
5
],
"text": [
"People are walking, talking heat generators. Normally, this heat gets lost into the air and spread out across the Earth. Thermal clothing is designed to trap pockets of air so when you heat it up, rather than blowing away to be replaced by cooler air, it stays next to you, keeping your heat close."
]
}
|
[] |
[] |
[
[]
] |
|
gf3xu
|
Can someone help me understand the relationship between mathematical models and not yet observed things / events?
|
Preface: I’m crappy at math. But I’m sure that’s already assumed.
OK, so a lot of things or events are predicted to exist / happen, based on various theoretical models. These complex theoretical models evolve slowly over time, getting continuously refined with experimentation and other data. So what’s predicted has pretty good ground for being so.
But beyond this I run into a conceptual fog. I think I will just throw some questions out here because I don’t really know what answers I’m looking for. I’m all over the place.
How do science models (Standard Model, etc.) differ from say a mathematical proof? I have this understanding that a mathematical proof is based upon unambiguous logic using only numbers or similar abstractions. To paint a picture, a mathematical proof is something that can be solved on a chalk board. Now contrast that with science equations, which require empirical evidence. So the way I’m thinking of science is like some scientist is only using math as a means to an end, finding whatever equations best models observable behavior.
But then I read about the Higgs boson, the innards of a black hole, and other things that are theorized, and to me the layman, it seems like these science equations are just so complex and evolved that I’m more struck by their ability to predict, than what they are actually predicting.
What exactly is going on when a mathematical equation predicts something in the real world? Do the equations that physicists use, predict a range of things, from the reasonable to the absurd, and it’s actually the physicist that is picking and choosing, not some mathematical certainty that the chalk board says must happen?
|
askscience
|
http://www.reddit.com/r/askscience/comments/gf3xu/can_someone_help_me_understand_the_relationship/
|
{
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"c1n408h",
"c1n444s",
"c1n4bc6"
],
"score": [
3,
2,
3
],
"text": [
"To some degree, mathematical models can predict things in the real world. When Dirac theorized the positron, for instance, he did so almost completely on the basis that some cool equations he came up with predicted it would exist. There was no physical evidence for the positron itself, but there was lots of physical evidence for the model that required the positron to exist.\n\nHowever, do note that people frequently take this too far. For instance, take a favorite of popsci and science fiction writers: the equations of general relativity allow tachyons to exist. There's nothing at all in the math that could be construed as prohibiting them from existing. But it's ridiculous to say that general relativity *predicts* them, because the math yields things like imaginary mass. We have no idea what an imaginary number for mass could possibly mean, and even if we developed some theory to explain it, that theory wouldn't be part of general relativity.\n\nSo to summarize: mathematical models can predict things. In fact, they have to for theories to be falsifiable. But very rarely is every part of a mathematical model used for some physical theory; frequently, only a certain set of values in the model is physically meaningful, so anything \"predicted\" outside of this range isn't actually a prediction.",
" > How do science models (Standard Model, etc.) differ from say a mathematical proof?\n\nWith a mathematical proof you start with axioms and reach a conclusion. With a physics theory, you start with some rules (like conservation of momentum) and what's called a Lagrangian, which is the mathy part of a theory. You try to find the path of your system that makes your Lagrangian as small as possible, and that path is the one that nature follows.\n\nTheory and experiment approach the same problem from two angles. An example I like is the Zeeman effect, which is what happens when atoms emit light in a magnetic field. You can do this in real life and see that the light is shifted up and down in frequency by a small amount. Then you can take the theory of the atom, ask what would happen in a magnetic field, do some math, and figure out that the frequency is shifted up and down by the same amount. The system works!\n\n**Or, a much simpler example**\n\nBasic physics tells us that when we drop something from a certain height, the time it takes to fall is proportional to the square root of the height you drop it from. How do we know that this theoretical prediction is correct? Well, we can test it with a ruler and a stopwatch. ",
"There are lots of distinctions, but the most critical is that proofs describe purely mathematical constructs, whereas models describe physical systems. The most important consequence is that a proof can say \"Given *A*, then *B*, *C*, and *D* **must** be true,\" while a model can at best say \"Given *A*, and ignoring anything else that might impact the outcome, we get *B*, *C*, and *D*.\" \n\nProofs are exact, but have limited usefulness in dealing with real-world systems where many physical processes are involved. Models can describe these complicated systems, but have their own pitfalls. Specifically, it's easy to make models that are too complicated to be useful. If you have a model with one parameter that predicts 100 measurements, that's a good model (because those measurements restrict the possible values of that parameter). If you have a model with 100 parameters that predicts one measurement, that model is useless (because that single measurement barely restricts the possible set of parameter values). One goal of scientific research is to come up with a model that describes the largest number of measurements given the smallest number of parameters."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
6j13j5
|
how long can someone be "knocked out" or put in a medically induced coma? and are there dangers of doing this ling term?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6j13j5/eli5_how_long_can_someone_be_knocked_out_or_put/
|
{
"a_id": [
"djawzn8"
],
"score": [
2
],
"text": [
"Medically-induced coma is used for two things: prolonged seizures that do not respond to anything else, and head trauma which is causing pressure within the skull to rise to the point where the brain may be forced down out of the skull. In the former case, it's been shown you can keep somebody induced for months. The latter is not a long-term illness, either it resolves or it kills you.\n\nThe main dangers of this therapy are first, that the drug itself drops your blood pressure significantly (and low blood pressure is a far bigger problem than high), which will require even more medication to manage; and second, that this therapy requires extended intubation which puts the patient at significant risk over time for an infection which, considering the state these patients are in, is liable to kill them."
]
}
|
[] |
[] |
[
[]
] |
||
3b11ad
|
how do we decipher ancient writings of civilizations that no longer exist?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3b11ad/eli5_how_do_we_decipher_ancient_writings_of/
|
{
"a_id": [
"cshtyyu",
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9,
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4
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"text": [
"Cross referencing languages that look similar, and or of same geographic area. There is more to it, but it's the tip of the ice berg. ",
"There are generally two ways to begin to work on this:\n\n1. Find a text in the mysterious language which is paired with another language that is less mysterious, and compare the two. This is what had to be done to understand Hieratic/Hieroglyphic Egyptian, by comparing it to Greek and Demotic Egyptian.\n\n2. Find numerals, then names, and go from there. This is what had to be done to understand Mayan written language.",
"Hints in other writings. For example, the Rosetta Stone has the same statement in three languages: Ancient Egyptian hieroglyphs, Demotic script and the lowest Ancient Greek. When this was discovered in the 1700s, it became a tool to decipher heiroglyphs since Ancient Greek was still studied. "
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
4dglaj
|
Were things as good during the Reagan era as modern-day Republicans say they were?
|
This question is not meant to imply that they weren't; I simply was not alive then and do not know. But the rhetoric often used is that everything would be perfect if we would go back to the time of Reagan.
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4dglaj/were_things_as_good_during_the_reagan_era_as/
|
{
"a_id": [
"d1qsw5z"
],
"score": [
8
],
"text": [
"Hard to evaluate this question as stated, but if you're asking, \"Why do Republicans like Reagan\", here's an answer I gave a while back: _URL_0_"
]
}
|
[] |
[] |
[
[
"https://www.reddit.com/r/AskHistorians/comments/30dvyd/why_is_ronald_reagan_so_praised_and_revered_by/cprlqb8"
]
] |
|
rqkd7
|
What is the largest stable molecule known? What molecule has the largest number of unique elements contained within it?
|
askscience
|
http://www.reddit.com/r/askscience/comments/rqkd7/what_is_the_largest_stable_molecule_known_what/
|
{
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"text": [
"I don't know about the second part of your question, but as for the first, synthetic polymer chains have no theoretical limit on length, and as such are described in terms of the repeating monomer, though technically the polymer may be a single huge molecule.",
"The molecule with the largest number of elements in it will probably be some kind of crystal with embedded impurities. A diamond is basically a single molecule.",
"To answer part of your question, things like proteins, fats, and DNA strands are just very large molecules known as macromolecules. The largest known protein is Titin. It has the chemical formula C169723 H270464 N45688 O52243 S912.\n\nSome notably large macromolecules are found in the human genome. The genome contains 3.2 billion base pairs which can be seen [here.](_URL_1_) That would amount to almost 100 billion atoms!\n\nBut to answer your question in full, **there's no such thing as the largest molecule.** A flawless diamond is just considered one big molecule! Whenever you have the biggest, you can just make it bigger.\n\n**There is also no molecule with the most amount of different elements.** For more info, see: _URL_0_ ",
"technically speaking, following vulcanization, the rubber in a car tire could be considered a single molecule\n\n_URL_0_",
"It depends solely where your definition of molecule ends.\n\nTechnically, the cores of many gas giants may be comprised of monocrystalline diamonds trillions of carats in size which are, technically, single molecules."
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.newton.dep.anl.gov/askasci/chem03/chem03401.htm",
"http://en.wikipedia.org/wiki/Base_pair"
],
[
"http://en.wikipedia.org/wiki/Vulcanization"
],
[]
] |
||
6kiaay
|
how have phone operating systems, today managed to reduce the time required to uninstall an app within a second, irrespective of its size(android os)
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6kiaay/eli5_how_have_phone_operating_systems_today/
|
{
"a_id": [
"djm963g"
],
"score": [
9
],
"text": [
"I can't destroy a building you're using in a second, but I can lock the main door in a second. The result will be the same for you, you can't use the building anymore. I'll then take my time to actually destroy it properly. \n\nYour phone doesn't completely delete all the stuff in a second. It is just deletes the icon that launches it, then it can take its time to actually delete all the data. \n\nAlso, deleting a 200Mb app doesn't mean actually doing something with all the 200Mb of actual switches in your memory. It just tells the phone that it can write something else on that part of the memory, which makes even the deleting process in background faster. "
]
}
|
[] |
[] |
[
[]
] |
||
baqzer
|
every now and then when you inhale deeply there is that extra room to breathe in really deep that feels great. what is the biological mechanism behind this?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/baqzer/eli5_every_now_and_then_when_you_inhale_deeply/
|
{
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"text": [
"A deep breath increases oxygen to the brain and stimulates the parasympathetic nervous system which promotes calmness.",
" > What is the biological mechanism behind this?\n\nWhich part, taking a big breathe, feeling like you have extra \"room\", or it feeling good?\n\n > Taking a big breathe\n\nOur body is pretty good at regulating our blood oxygen level - but it isn't perfect and sometimes our oxygen levels drop a little. We're actually really bad at recognising low oxygen levels, but we're really good at noticing a buildup of carbon dioxide.\n\nWhen the levels of CO2 in our blood gets too high, our brain tells our lungs to take a big breathe to get rid of a bit of extra CO2 and get a bit of extra oxygen. You'll probably also breathe a little bit faster and more deeply for a minute or two after the big breathe, but we tend not to notice that because it's fairly normal.\n\n > Extra room to breathe\n\nIt's always there, it's just that most of the time we don't need full lungs. Our bodies are designed for our peak performance, not average... when we're resting, we only need a smaller proportion of our lung capacity, less than half. We only use the extra room (expanding our lungs fully) when we've been exercising heavily and need more oxygen, or for these occasional \"big breaths\"\n\n > That feels great\n\nIt feels good for a few reasons\n\n1. Your brain \"rewarding\" you for taking a big breathe by releasing happy hormones, like the endorphine rush we get when we hug someone we like, or the adrenaline rush from a big drop on a rollercoaster, our brains give us chemicals we like to encourage us to do certain things\n2. Like a cold drink when we're thirsty, the cool (usually) air entering our lungs can feel nice\n3. It's like when you yawn/stretch - when we take a full breath it stretches our chest muscles. Stretching allows extra blood into our muscles which helps bring oxygen to them and remove any toxins. This prompts our brain to release some more endorphines because it likes that.",
"I have a fairly well-educated guess. It's just an increase in lung surface area that's adding some extra O2 to your blood, which generally feels good. Here's the longer version:\n\nThe lung is pear shaped. Most of the time, when you inhale, you take in what's called the \"tidal volume\" of the lung -- a smallish inhale, and a smallish exhale. It's about 1 L or so, with the midpoint around 3 L. Most of the air inhaled normally goes to the middle-bottomish area of the pear. \n\nThe part of the lungs that actually take in the air and exchange oxygen with blood are called alveoli. This means the alveoli in the middle-bottomish part of your lungs get most of your oxygen.\n\nWhen you inhale very forcefully, by engaging your diaphragm and a portion of your intercostals, you can actually inhale a volume of air that is equal to your total lung capacity (6-7 L in an adult). When you do this, you fill up ALL of the lung, and the bronchioles and alveoli that are not typically transferring O2 into the blood get in on the action. You can think of this as filling everything from the middle to the top of the \"pear.\"\n\nIf nothing else, your body knows how to put extra oxygen to good use. It's so good, in fact, that adult hemoglobin has to be \"worse\" than fetal hemoglobin, or we'd have too much oxygen! So we're calibrated to take shallow breaths when we're breathing normally.\n\nThe hypothalamus does respond to blood oxygen levels, but the most direct neurological control of respiration rate comes from the medulla. I am skeptical. It is certainly true that portions of the medulla do communicated directly with the hypothalamus. The next question would have to be, which primary messenger hormone is released to the pituitary, and what secondary hormone does it release? This makes a seemingly complex question very easy! \n\nSince the OP describes this as a rapid phenomenon, we know it must be a peptide hormone rather than a steroid one -- the onset and duration match. Since the anterior pituitary produces the peptides, we can look at the \"FLAT\" portion of the \"FLAT PEG\" acronym and see if there's a hormone that matches the symptoms.\n\nThe only hypothalamic hormones that get anywhere near inducing the physiology OP describes are cortico-releasing factor, but you gotta squint your eyes, turn your head sideways, and REALLY want to see it.\n\nMost likely, he's just exposing extra lung surface area to oxygen and modest hypoxia feels pretty good. \n\nI'm no judge, and I'm open to other ideas, but I've love to gavel an ELI5 to completion just once, and say \"case closed,\" like in all of that Law and Order I grew up on.\n\nEDIT - Sorry for typos. It's my day off, so breakfast is Wavy Lays and cheap American beer. Butter fingers plus bubbly brain can make for a hell of a menagerie of typos."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
6n6vnv
|
how is it not considered false advertising for a company to make commercial that says an offer is only good for a limited or certain amount of time, then play it for years?
|
For example: I've seen the *same* advertisement for at least a decade with the exact same wording, actors and information that say it's only a 'Limited Time offer'
& nbsp;
Or commercials that say "Call within the next twenty minutes and get < bonus deal > " (and even include a timer that counts down to imply urgency) but play multiple times a day for a long stretch of time.
& nbsp;
It strikes me as very disingenuous and I thought it would be considered misleading
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/6n6vnv/eli5_how_is_it_not_considered_false_advertising/
|
{
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"text": [
"In the fine print they probably reserve the right to alter, extend, cancel any promotions at any time without any obligation to inform customers.",
"What is \"a limited time\"? Is it 20 seconds? 20 minutes? 20 hours? 20 days? 20 years? 20 decades? 20 centuries?\n\nThanks to ambiguity, \"a limited time\" can be any length of time whatsoever, so long as that timeframe has some sort of limit. Hell, the \"limit\" could be \"until we go bankrupt\". ",
"It is worded so that you work on an assumption and not the actual facts. The assumption that you make, based on the wording, is that if you call outside of the given time frame that you would NOT get the special pricing, but that's not what they said. They just said that if you call in the next 20 minutes you will DEFINITELY get special pricing. That's because it's ALWAYS that price regardless of when you call."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
1ghwc4
|
why animals can breed with their own family without genetic problems but humans cant
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1ghwc4/eli5_why_animals_can_breed_with_their_own_family/
|
{
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"text": [
"Animals can not be bred with their own families without causing occasional problems.\n\nThis is one of the reasons why most pure-bred dogs have a [shorter life-expectancy](_URL_0_) than mixed breed or mongrels. (There are other reasons for this too, though.)",
"Humans can breed with their family. The chance of biological defects takes a few generations. ",
"Simple answer: that's just not true. The question is wrong.",
"Animals can't breed with their own family either, they have risks of genetic problems as well. Inbreeding is the main reason purebred dogs have so many problems and mutts are considered healthier. ",
"[Another thread about a Tiger with brother/sister parents](_URL_0_)\n\nThe first comment here is very helpful"
]
}
|
[] |
[] |
[
[
"http://users.pullman.com/lostriver/breeddata.htm"
],
[],
[],
[],
[
"http://www.reddit.com/r/pics/comments/18wict/kenny_a_white_tiger_with_down_syndrome/"
]
] |
||
1z6z3o
|
What would the leaders of the American Revolution have expected to happen should the revolution have failed?
|
There's no such thing as a "sure thing" in a war or Revolution, so I suppose events could have lined up in a way that ended with the British putting down the Revolution. What would the leaders have expected to happen to them if they weren't successful - was "hanging together or separately" a real concern, or would the punish have been different?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1z6z3o/what_would_the_leaders_of_the_american_revolution/
|
{
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"text": [
"I think it's a stretch, without a firm source, to say the revolutionaries would have definitely been hanged for treason if the war went poorly. If the land-owning, formerly-respected members of the revolution sued for peace, there could have been a possibility of some manner of pardon, depending on each side's respective position in the war and their desire to conclude the war on favorable terms. \n\nFor example, formal discussions between revolutionary leaders and the British took place on the subject of ending hostilities -- such as the **Staten Island Peace Conference**, where John Adams and Ben Franklin met with Lord Howe after the rebel loss in the Battle of Brooklyn. So I don't think a negotiated peace is out of the question, even though it proved untenable at that point.\n\nBut we could say that Franklin and Adams were able to meet with British authorities without being arrested on the spot. They were treated as legitimate negotiators and recognized as such, at least during the period when they had troops in the field. If those troops were decimated, British reception would naturally be less hospitable, but the question is whether the revolutionary leaders would have sued for peace after defeat became apparent, but before the British destroyed their ability to wage war. That question seems impossible to answer. We know the rebel leaders had a \"do or die\" attitude at the start of hostilities (paraphrasing Patrick Henry), but that was before they had established themselves as enough of a political and military annoyance to merit negotiation. \n\nAnother fact of note is that in August 1775, King George proclaimed that any colonist who took up arms was engaged in treason, yet this was not enforced in the actual conflict in the following years. Alan Valentine's biography of Lord Germain notes that despite his command, **British generals did not hold treason trials** and instead held captured rebels as POWs, contrary to official royal decree. The capture of numerous British troops at Saratoga provided additional incentive not to hang captured rebels. \n\nThis is not to say that rebel prisoners were treated with hospitality. Far from it. *See, e.g.,* Lang, Patrick J., \"The horrors of the English prison ships, 1776 to 1783, and the barbarous treatment of the American patriots imprisoned on them.\" But what it does show is that the British were not fully committed to treating the uprising as a treason issue, at least so long as military and political considerations were at play. \n\nInteresting footnote - In 1990, lawyers from the US and the UK held a mock trial in a British court where they **tried George Washington for treason**. [The court found Washington not guilty of all charges](_URL_0_). Somehow I doubt that an 18th century UK court would be as forgiving, but again, it's hard to say exactly what terms a Colonial surrender would entail, depending on the strategic situation. \n\n**EDIT**: A bit of checking shows that John Adams learned many years later that his name was on a list of people specifically excluded from any offers of pardon Lord Howe might make to the rebel leaders. *See* Edgar, Gregory T., Campaign of 1776: the Road to Trenton (1995). So that might be the best answer. Pardons were contemplated, but not for all. \n",
"In *Washington: A Life* (Pulitzer Prize for Biography 2011), Ron Chernow says that George Washington planned to flee to his lands in the Ohio Valley that he acquired between the French and Indian War and the Revolutionary War. Chernow didn't go into much more detail than that--such as how he expected to stay safe once there, which Washington probably hadn't considered either--but that was his plan. "
]
}
|
[] |
[] |
[
[
"http://news.google.com/newspapers?nid=1298&dat=19901020&id=0v1NAAAAIBAJ&sjid=vYsDAAAAIBAJ&pg=6672,3881261"
],
[]
] |
|
4yqdev
|
why does it seem that mercury(ii) thiocyanate is creating new mass when heated, therefore defying the law of conservation of mass?
|
This is what I'm talkng about
_URL_0_
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/4yqdev/eli5_why_does_it_seem_that_mercuryii_thiocyanate/
|
{
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10
],
"text": [
"Well, it's not creating new mass, because that would indeed break the laws of physics.\n\nThe fire causes the releases of gasses, which cause the entire thing to blow up like a sort of foam. The resulting material is very light.",
"It's not creating new mass, it's creating new _volume_, the same way your mom does when she whips egg whites into a meringue or when a cake or souffle rises in the oven. Whipping egg whites incorporates air bubbles into the protein structure of the egg whites. Similarly when baking a cake, the baking powder in the batter releases carbon dioxide when heated releasing the gas bubbles into the batter, which get trapped in the protein (gluten) structures. \n\nSimilarly, the chemical reaction you're seeing is releasing gas (carbon dioxide and sulfur dioxide) into the element so it \"rises\" like a really gross snake cake. \n\nAfter the reaction the mass is probably somewhat less because some of the matter has been converted to gases that escape. But the volume is greater because of the gas bubbles trapped in the element. "
]
}
|
[] |
[
"https://youtu.be/xI_xTTqNj6o"
] |
[
[],
[]
] |
|
33ybmi
|
how can population keep growing, and poverty declining, in a world that has limited resources?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/33ybmi/eli5_how_can_population_keep_growing_and_poverty/
|
{
"a_id": [
"cqphsds"
],
"score": [
4
],
"text": [
"We keep getting better at using/gathering those limited resources... and \"limited\" in this sense is still a really large number."
]
}
|
[] |
[] |
[
[]
] |
||
3zezar
|
how does service in a (posh, i suppose) restaurant work - from the maitre d' taking orders, to what happens in the kitchen.
|
I ask because I'm watching Bradley Cooper's movie "Burnt" which is about a 2 star Michelin chef. From what I see, he seems to not cook at all, but receive orders, yell them out, and then 'ok' the dish to go.
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3zezar/eli5_how_does_service_in_a_posh_i_suppose/
|
{
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"cylj817",
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2
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"text": [
"In any proper restaurant, you will have 2 major teams: Front of House, and Back of House. Both of these teams report up to the Owner and his team. Let's look at Front of House. In the front, you will have the Maitre d' running the show. He is responsible for the general operations of the restaurant...open/close, and all the servers and wait staff. It would be unusual for the Maitre d' to be taking orders from customers. He will be certainly watching the tables and service team to make sure things are running properly. If there is a bar, the bartender might be front-of-house also. Back is where the kitchen is... and where the food is prepared. The kitchen is run by the Exec Chef. This guy is responsible for pretty much anything that goes on in there. The Exec will have a Sous Chef who acts as his second-in-command and runs things when the Exec is busy elsewhere. There might also be less-talented junior cooks doing prep, running the deep-fryer, grill, soup or pastries for dessert. The mechanism for \"building\" the food is called \"the line\". Basically, the order will come in from the floor (Front of house) and it will be put into an electronic system (with screens) or printed out by a printer. The orders are then stacked up in order...which is critical, as each table should be served at once, and each table might have several orders which take different times to prepare. The Chef basically calls shots...like a quarterback. He decides what to work on, when, and assigns tasks to the team in the kitchen. Some kitchens involve a lot of yelling. \nWhen the dishes come together they are plated (put on plates) and placed on a long counter where a server (often called a runner) will deliver them to the table. \n\n The Chef will very likely be doing a lot of the cooking, but the heavy lifting or simpler tasks (making french fries, making soup) for example will be offloaded to other cooks. The Chef (chef is \"chief\") generally has the most skill, most knowledge and basically has the ability to run all aspects of the kitchen. He (or she) is the leader in there. Ideally, the Chef will have a good team so things can run smoothly. If not the Chef either has to fill in and get things done, or assign someone else to take of the slack.\n\n Both front and back will report to the Owner, who controls the money, and often the menu. ",
"/u/OttawaTechVeteran 's explanation of the service is pretty concise. Though specific operating details may vary from kitchen to kitchen. \n\nThe one detail relating specifically to your example (I haven't seen the movie) that seems left out is the role of an expediter, which sounds more like the role Cooper's character takes. It looks and sounds easy, but being a good expo is one of the toughest jobs in the back of the house. It is that person's job to keep the back of the house running on time, and is the last person to spot check a completed dish for quality before the runner picks it up, so it's not uncommon that one of the higher level chefs will do the expediting in lieu of cooking."
]
}
|
[] |
[] |
[
[],
[]
] |
|
34xstz
|
why do you get a closer shave when you go over the same area multiple times?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/34xstz/eli5_why_do_you_get_a_closer_shave_when_you_go/
|
{
"a_id": [
"cqz1ht0"
],
"score": [
2
],
"text": [
"because the first pass takes some hair, and some of the top layer of dead skin. so the second pass is closer to the root of the hair.\n\npro tip: exfoliate before you shave. then do one pass. less razor bumps, healthier skin, closer shave."
]
}
|
[] |
[] |
[
[]
] |
||
1dj0sa
|
What were some true triumphs in Hitler's military control, and what were some undeniable examples of his incompetency?
|
Open for all input. Thanks!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1dj0sa/what_were_some_true_triumphs_in_hitlers_military/
|
{
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"text": [
"Triumph: Hitler attacked Poland, and then the following spring France, at a time when most of his generals felt that Germany was far from ready to fight. (They wanted to wait until 1945.) In both cases they achieved near-total success in a breathtakingly short time.\n\nFailure: Hitler felt that because Russia was \"rotten\" to the core that it could therefore not put up a significant sustained military resistance. His direction of the Russian campaign, therefore, was ill-planned, confused, and did not give nearly enough respect to the tenacity and brutality of both the Red Army and the Russian winter. His insistence on defending captured ground 'to the last man' exacerbated the problem, as perfectly good units in bad positions were sacrificed instead of pulled back. In the end, his whole boneheaded running of the Barbarossa campaign cost millions of lives shed to no purpose, and hastened the end of Nazi Germany by years.",
"One could argue he badly misused the V class rockets. Instead of using them against military targets, he used them in a vengeance program, launching them at civilian targets in England. ",
"I would credit the victory over France more to his generals, especially Guderian. The German doctrine at the time allowed for significant leeway on the part of field commanders and many of them showed incredible aggressiveness that led to that victory. Hitler and much of his staff at the time did not want the Panzer divisions to keep pressing into France, they feared that the lines would become too vulnerable and France would be able to counterattack. The Panzer divisions were actually ordered to stop, but Guderian pretended there was a problem with the radio and claimed he didn't receive the order. Then, he requested permission to send an \"armed recon\" mission to scout ahead -- and then he sent his whole division forward, claiming they were all part of the \"recon\" team. Eventually, Hitler asserted a halt order that is still a little controversial among military historians, and it caused the German advance to stop long enough for the Dunkirk evacuation. Had Hitler not given this order, Dunkirk may not have happened.\n\nSources for all this: _URL_0_ and _URL_1_\n\nOverall, the German army seemed to struggle most with intelligence (not meaning they were dumb, I mean in terms of getting information on the enemy, and counter-intelligence = keeping the enemy from finding out about you). They didn't seem to have great intel, and the allies often had solid intel on German movements, which plagued a lot of the German operations.\n\nIt seems that over the course of the war, Hitler went from an open policy, allowing his field commanders to improvise at their discretion, which tended to work well and give them flexibility -- to a more micro-managing, hands-on approach as the war went on. This kept the army from being able to respond as quickly and effectively.",
"One position I haven't seen mentioned is his initial *construction* of a viable army and air force in the face of the Versailles Treaty. His schedule for completing the navy wasn't to be complete until after the war actually ended; I believe only two battleships the Graf Spee and Bismark were completed, and quickly sunk, and that the u-boat fleet can be considered \"decimated\" by the end.\n\nPerhaps some truer historians can speak to this?"
]
}
|
[] |
[] |
[
[],
[],
[
"http://www.amazon.com/The-Blitzkrieg-Legend-1940-Campaign/dp/1591142954/",
"http://www.amazon.com/Quest-Decisive-Victory-Stalemate-Blitzkrieg/dp/0700616551/"
],
[]
] |
|
2vcij5
|
how did you distinguish friendly and enemy knights during the war of the roses when knights did wear plate armor?
|
So lately I have been reading about the war of the roses and have been looking up paintings of some of the battles. I started noticed that knights almost didn't wear any tabard or any other indications which side they belong to.
[an example.](_URL_1_)
In this painting the knights/men at arms don't wear any cloth that can indicate which side they belong to while the common foot soldiers do.
And it's the same thing in this [painting](_URL_0_)
So did knights during the war of the roses wear a tabard over the armor? if not how did they distinguish friendly and enemy knights?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/2vcij5/how_did_you_distinguish_friendly_and_enemy/
|
{
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],
"text": [
"The first example you show is a modern painting by Graham Turner. The second is a manuscript illumination, probably painted by someone who never saw the battle depicted. So I would caution against concluding that, because of these depictions knights did not wear anything to identify thselves. I need to look up my own sources on Livery Coats before I say more."
]
}
|
[] |
[
"http://upload.wikimedia.org/wikipedia/commons/e/e9/Battle_of_Barnet_retouched.jpg",
"http://www.multiwords.de/genealogy/BattleTewkesbury.jpg"
] |
[
[]
] |
|
1j945t
|
Does it help to read works in their original languages?
|
For example, if I were to read Cicero's *Orations*, should I read it in its original Latin?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1j945t/does_it_help_to_read_works_in_their_original/
|
{
"a_id": [
"cbccbmg"
],
"score": [
3
],
"text": [
"Yes and no.\n\nBasically it depends on your Latin. Reading and translating stuff ancient languages is both a science and an art. There is more to Latin than 'Latin': [there are several different sorts](_URL_0_). Hence why there are so many translations of different Latin sources. If you read something using 'your Latin' then you might miss out on stuff within the text.\n\nWhich is not to say that you shouldn't try to read the original (known) text, just that there's more to reading Latin than 'reading Latin'. Studying the 'Latin of the ancients' is an intense scholarly field.\n\nTl;dr it depends."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Latin#History_of_Latin"
]
] |
|
an0d70
|
why does black ink often appear a metallic purple/orange colour?
|
[deleted]
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/an0d70/eli5_why_does_black_ink_often_appear_a_metallic/
|
{
"a_id": [
"efpvdig"
],
"score": [
2
],
"text": [
"Because black is all of the colors. It has purple and orange in it. So depending how the light hits it depends what shines "
]
}
|
[] |
[] |
[
[]
] |
|
f5bpf6
|
Does the quality of gold impact its conductivity?
|
This is for a DnD campaign, just to clarify. One character is attempting to con another into buying her low quality/low karot gold in exchange for his high quality because the low one will "be a better conductor" for electricity.
I was wondering if she's actually right in this?
|
askscience
|
https://www.reddit.com/r/askscience/comments/f5bpf6/does_the_quality_of_gold_impact_its_conductivity/
|
{
"a_id": [
"fhxstxd",
"fi041jq",
"fi2o6w8"
],
"score": [
2,
7,
2
],
"text": [
"Well, yeah, but I would guess not to an extent that is meaningful in a DnD setting. But that depends on your story.",
"The main conductors of electricity in metals are free electrons. Impurities serve as additional scattering sources for electrons, reducing their mean free path and lowering the conductivity. Even if it's impurities of silver or aluminum (metals that conduct better), these atoms do not perfectly merge into the crystalline structure of gold, and these deviations from the ideal crystal are what causes additional scattering. Although I can imagine a situation in which impure gold would have higher conductivity - and that is if it would have large embedded crystallites of said silver or aluminum. Large enough that their grain boundaries don't matter much (so at least a couple hundred nanometers). But that would probably have a visible effect on gold she's trying to sell.\n\nHowever, I think I know where your player got her idea from. In semiconductors, the situation is usually very different, as certain impurities can greatly affect the number of charge carriers and their mobility. So if your player would be selling specifically doped silicon, she could make such a claim.",
"It all depends on your definition of quality. If it's an uncontrolled mix of random, naturally occurring impurities, then you'll most likely have lower conductivity. But in certain, highly controlled and precise doping situations, or the other scenarios mentioned by other replies, you could have drastically different, borderline magical properties."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
7pnjle
|
How did scientists practice chemistry before the mass production of chemicals?
|
I did a practical today, where I used a lot of different chemicals in different concentrations. I don't think people in the 18th century were able to produce magnesium sulfite of exactly 1M, so how did they do their research?
|
askscience
|
https://www.reddit.com/r/askscience/comments/7pnjle/how_did_scientists_practice_chemistry_before_the/
|
{
"a_id": [
"dsjbcx3",
"dsjhhzu"
],
"score": [
4,
21
],
"text": [
"If you don't get an answer here, you can try /r/askhistorians, /r/historyofscience, or /r/philosophyofscience",
"Well for starters you have to forget about molar concentrations, since they didn't know about molecules in the 18th century, let alone Avogadro's number. If they measured concentrations, it was in terms of volume or weight %. Magnesium was not known as such in that time either. They did know of \"Epsom salt\", which is naturally occurring magnesium sulfate. \n\nPeople did research by studying if and how things reacted, and the properties of substances. At the time they had various theories (the most famous of which is phlogiston theory), almost none of which were correct. By the late 18th century Lavoisier, the father of modern chemistry, had figured out that mass was conserved in reactions. They had identified things that didn't seem to be able to be broken down into other stuff, and called those 'elements'. However, it wasn't until Dalton's 1805 atomic theory that you have atoms, molecules and elements in fully the same sense as today.\n\nCirca 1795 a chemist might be figuring out that if you take the element sulphur*, and heat it in a vacuum, nothing happens. If you heat it with oxygen you get a nasty gas (sulphur dioxide), which in turn reacts with water to form sulphuric acid. (or 'oil of vitiol'), which could be identified by its properties and how it reacted. Add metallic iron and you get hydrogen gas and a salt they knew then as 'green vitriol'. Heat that and water is given off, heat it further and you get back the nasty SO2 comes back and you get 'red ochre' (iron(III)oxide), or 'mars red'. (Mars being iron, venus copper, mercury is mercury, etc) \n\nIt was around this time they did precisely this kind of thing, deducing what elements were part of what compounds, and introduced the beginnings of the nomenclature we use today - the 'vitriols' became known as sulphates, because vitriols contained sulphur (and oxygen), alchemical planet names were substituted for the usual names of metals. \n\nSo that's the kind of thing they were busy with at that time. Much of the first half of the 19th century, once you had atomic theory, were spend sorting out the (relative) weights of the elements, the elemental composition of compounds, and their formulas. Which also required sorting out the distinction between the formula and the 'empirical formula' (the ratio of elements). Dalton believed his atoms always combined in the simplest possible ratios, which was false. (e.g. hydrogen peroxide is H2O2 and not HO)\n\nSo in short, they were not working with precise concentrations of compounds then, because chemistry was very much a _qualitative_ study. Conservation of mass and stochiometry started in 1774, and only there did they start finding out the things we needed to know to be quantitative.\n\n(* As for where the sulphur came from - child laborers working in horrible slave-like conditions on the slopes of Mount Etna in Sicily. Sad fact.)"
]
}
|
[] |
[] |
[
[],
[]
] |
|
r5mnl
|
Is there a particular reason as to why Tutankhamen's tomb wasn't discovered before 1922?
|
Did it have something to do with his father (?) trying to replace Egypt's many gods with one god? Was there a conscious effort at the time to hide all traces of this act, including the location of Tut's tomb? Or was it just luck?
EDIT: Might want to clarify.. When I say "discovered before 1922" I also mean "Wasn't looted in ancient times".
Thanks!
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/r5mnl/is_there_a_particular_reason_as_to_why/
|
{
"a_id": [
"c4357qk"
],
"score": [
12
],
"text": [
"Multiple reasons, as far as I can tell. I don't think it had much to do with his father (by which you mean Akhenaten, I imagine), despite the stigma that we assume came with his progenitor's name. After the glamor and chaos of Akhenaten's rule, and compared to the pharaohs of the past, Tutankhamen (formerly Tutenkhaten) was just a minor blip on the radar. His overall anonymity in the scale of things meant that fewer people realized there was even a pharaoh to steal *from*, as compared to more obvious and notorious kings like Seti I, Khufu or Djoser.\n\nBy the late 1800s, despite the frenzy of Egyptomania, most people assumed that there was nothing left to find in the Valley of the Kings. An ironic surprise that may have saved Tut's tomb from looting in more contemporary days is the excavation Seti I's tomb by the flamboyant Italian [Giovanni Belzoni](_URL_1_) (in 1817, I believe). He was little more than a publicly-sanctioned tomb-robber himself, who was not prone towards scientific examination. He was mostly interested in treasure and fortune. While digging into the tomb, he and his workmen may have inadvertently shoveled more dirt over the burial location of Tutankhamen's tomb several hundred feet away.\n\nIt was only Howard Carter's dogged determination, luck, and Lord Carnarvon's funds and patience that allowed him to actually uncover the tomb. But he wasn't actually the first to discover it. He was likely the first to *rediscover* it. When they had actually unsealed the tomb, they found a few [looters trenches](_URL_0_),\n which only made it into peripheral chambers. These were probably ancient thieves. "
]
}
|
[] |
[] |
[
[
"http://ngm.nationalgeographic.com/ngm/0506/feature1/text2.html",
"http://en.wikipedia.org/wiki/Giovanni_Battista_Belzoni"
]
] |
|
1yjvpd
|
Did pop culture exist in the post-Roman period?
|
I've comes across quite a few references to aspects of Roman culture which are identifiable as being 'pop culture', even if not in a directly modern sense, but I don't know that I've ever seen mention of anything vaguely recognisable as such in the post-Roman period (in the West, at least) until comparatively recent history. I generally don't subscribe to the 'dark ages' concept, so I'm curious...
Did pop culture cease following the Roman period? If so, when is the next time we see something identifiable as such occur in the West?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/1yjvpd/did_pop_culture_exist_in_the_postroman_period/
|
{
"a_id": [
"cfle9ze"
],
"score": [
2
],
"text": [
"When you write \"post-Roman,\" do you mean the early middle ages? \nA lot of the art and culture that has been preserved from that period is sacred, partly because the institutions recording everything were affiliated with the church. You can't really separate religious life from everyday life in this time period (or magical and \"real,\" for that matter), so your question about \"pop culture\" makes some assumptions that won't necessarily apply to this era. That said, there are a lot of examples of what might be called \"pop\" culture -- preserved in songs, song texts, folk tales, and visual art. You might be interested in the Carmina Burana (not the Carl Orff music, though), Roman de Fauvel, Perceval, works by Christine de Pizan, the Jeu de Robin et Marion, Beowulf, the poetry and songs of Guillaume de Machaut, and the Roman de la Rose. The Carmina Burana are collected songs of wandering scholars, often dealing with themes of games, drinking, sex, and social criticism. The Roman de Fauvel is a satire making fun of the corruption of those in power, and it was wildly popular. "
]
}
|
[] |
[] |
[
[]
] |
|
3zdtde
|
Why does hand sanitizer kill the bacteria and viruses on my hands, but not the living skin cells directly adjacent?
|
askscience
|
https://www.reddit.com/r/askscience/comments/3zdtde/why_does_hand_sanitizer_kill_the_bacteria_and/
|
{
"a_id": [
"cylr0ro"
],
"score": [
12
],
"text": [
"Sanitizer kills in two ways: it draws out water and dehydrates things, and it disrupts macromolecules, leading them to precipitate/aggregate and become nonfunctional. Both of these effects contribute to make pathogens non-infectious.\n\nSkin is remarkably resilient and can tolerate both of these effects easily, it can dehydrate, but is hydrated independently from below. It is resistant to the precipitation effect because the proteins that cross-link and make the matrix of the skin are in a way already insoluble and cross-linked. Doing it a bit more makes no difference."
]
}
|
[] |
[] |
[
[]
] |
||
a3aqnh
|
how do people make those picture mosaics where the image is made up of hundreds of smaller, different versions of the same subject?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/a3aqnh/eli5_how_do_people_make_those_picture_mosaics/
|
{
"a_id": [
"eb4nunc",
"eb4nw8q"
],
"score": [
6,
3
],
"text": [
"essentially you give a program a folder full of pictures (alot!) and it calculates the color value of each, if reduced to 1x1 pixel. then you give it a picture that you wanna make \"a mosaik\" this way and it runs through all its pixels, trying to find the closest fitting picture by color-value. Then it just inserts a small version of the found pictures for all pixels (resulting in a bigger picture ofc).\n\nmore professional versions also take into account multiple resolutions (not just 1x1), add edge detection and feature detection to have better fits, and ofc theres now also machine learning algorithm that can try to match variable sized patches (these are more like collages)",
"Mosaic software. You can create them online by choosing the primary picture then choosing at least 100 secondary pictures."
]
}
|
[] |
[] |
[
[],
[]
] |
||
8rj6dw
|
why is the feeling of silverware hitting your teeth so uncomfortable?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/8rj6dw/eli5_why_is_the_feeling_of_silverware_hitting/
|
{
"a_id": [
"e0rqhug"
],
"score": [
5
],
"text": [
"Soft material will absorb impact much better than hard material. Think about hitting that spoon on your shin and your calf - the shin will feel much weirder than your calf. As for WHY that sensation is so much more uncomfortable, I could only suppose it’s the way we evolved pain to avoid injuring ourselves - certain things hurt more than others."
]
}
|
[] |
[] |
[
[]
] |
||
3naywt
|
why do defendents on tv court shows defend their case so vigorously if they don't pay settlements out of pocket?
|
Defendents seem to get genuinely upset when the judge is not siding with them even when they have no real case? Is it just an act?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/3naywt/eli5_why_do_defendents_on_tv_court_shows_defend/
|
{
"a_id": [
"cvmfbny",
"cvmfihz",
"cvmhhuv"
],
"score": [
4,
4,
3
],
"text": [
"Because people really want to be right, and want to be vindicated about being right on national television. That's why they went on the show on the first place. They don't like to be proven wrong.",
"One, it's an act. Two, they get the appearance money if they don't have to pay it in court.",
"Everyone has their own personal sense of justice and outrage. Have you ever heard siblings or lovers bickering, even though there is nothing at stake other than pride?\n\nAlso, the appearance money is first used to pay the judgment, and then what is left is split between the two sides. So there is money at stake."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
|
dlge1z
|
how can big game developers like rockstar or valve seal all the informations about their biggest titles - like gta 6 or half life 3 - despite having hundreds or even thousands employees around the globe?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/dlge1z/eli5_how_can_big_game_developers_like_rockstar_or/
|
{
"a_id": [
"f4ptunm",
"f4puavk"
],
"score": [
3,
2
],
"text": [
"NDAs (non disclosure agreements), employee contracts and possibly legal action tend to keep employees right lipped",
"NDAs, yeah, but also the tried and true method of spies, terrorists and anyone working with Tom Holland. The guy working on the physics doesn't need to know what the voice actor is saying to do his job properly."
]
}
|
[] |
[] |
[
[],
[]
] |
||
tnex6
|
what are 'mach' points of speed?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/tnex6/eli5_what_are_mach_points_of_speed/
|
{
"a_id": [
"c4o3nzv",
"c4o72cx"
],
"score": [
2,
2
],
"text": [
"Mach 1 is the speed of sound (340.29 m / s)\n\nMach 2 is twice the speed of sound (680.58 m / s)\n\n",
"Every different material has a different speed that kinetic energy naturally wants to move through it. That speed is called Mach 1, and the \"Mach number\" is just the speed of whatever you're looking at divided by the speed at which energy moves through that specific material (whether it be air, water, steel, etc). \n\nCoincidentally, sound is a type of energy--and so instead of saying \"the speed energy travels through this material\" we say \"the speed of sound through ----\" just for convenience. \n\nSonic booms happen because when an airplane wing moves faster than the molecules naturally want to move (the speed of sound) , the wing ends up separating two sheets of air that end up clapping back together. The sonic boom is that clap. When the plane is moving slower than the speed of sound there's no sonic boom because the air molecules can leisurely fill in the space where the wing just was. "
]
}
|
[] |
[] |
[
[],
[]
] |
||
31lnza
|
why do people cough up dark tar when they quit smoking, but it doesn't happen as much when they are still smoking?
|
It seems like people "cough up a lung" and get all the black stuff out after they quit smoking, but it doesnt happen so much when they are still actually smoking?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/31lnza/eli5why_do_people_cough_up_dark_tar_when_they/
|
{
"a_id": [
"cq2q2v8",
"cq2q5xp"
],
"score": [
2,
5
],
"text": [
"The short answer is that smoking suppresses the function of the lungs, thus hindering their ability to remove toxins. When you quit smoking, the body quickly starts on clearing things out and repairing itself.",
"There are little hairs in your lungs that move things that don't belong in your lungs out. They are called \"cilia\" and they have a waving motion that creates this ability. The tar and chemicals in the cigarette smoke paralyze the cilia so they can't do their job. When the person quits smoking the cilia eventually start to work again - and that's when the tar starts coming out because the cilia is doing it's job again."
]
}
|
[] |
[] |
[
[],
[]
] |
|
3bk5do
|
why is it that counting down is universally easy, but keeping rhythm is not?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/3bk5do/eli5_why_is_it_that_counting_down_is_universally/
|
{
"a_id": [
"csmv2cf"
],
"score": [
2
],
"text": [
"I'd say it's a practice thing. Also musical meter isn't always directly linked to our understanding of the passage of time. Where most people have a good idea of what a second feels like, not everyone can instantly grasp a what a beat is in a given tempo w/o a metronome."
]
}
|
[] |
[] |
[
[]
] |
||
a3siky
|
When are the earliest examples of pornography from, and what were the main forms of consumption before mass media?
|
There are many cavedrawings from primitive peoples, have any of those found seemed to include any form of pornography? Do we know the first documented example of porn?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/a3siky/when_are_the_earliest_examples_of_pornography/
|
{
"a_id": [
"eb8s5y7"
],
"score": [
5
],
"text": [
"I have answered this a [few](_URL_2_) [times](_URL_4_] [before](_URL_3_) and you might be interested [in my book](_URL_1_) but here was the most recent summary of this:\n\n\nI'm adapting this from some older answers. \n\n\nHere's the tricky thing about your question--do you mean 'porn' in the sense of moving visual art of people doing erotic things? Then in 1894 Edison's studio recorded a vaguely erotic short, titled Carmencita, which featured a Spanish dancer who twirled and posed on film for the first time. The short was considered scandalous in some places because Carmencita's underwear and legs could be seen in the film. A couple of years later, in 1896, the same studio recorded The May Irwin Kiss, an 18 second film of a Victorian couple kissing (in an incredibly awkward and forced manner). According to Maximillien De Lafayette, this scene in particular caused uproar among newspaper editorials, cries for censorship from the Roman Catholic Church, and calls for prosecution—although these calls do not seem like they were followed up on.\n\nOr perhaps you mean film of people actually doing the deed? Then the oldest surviving work we have is *L'Ecu d'Or ou la Bonne Auberge*, which was first distributed in 1908--and features a man coming to an inn somewhere in france. The inn has no food, but the inkeeper is desperate for food and offers a very different type of food -- his daughter. And then, just because a third woman has to come and join in on the fun. However, this film only survives in a few places now, censors managed to destroy most copies of this film. \n\nThe earliest surviving American film, available on [Wikipedia of all places,](_URL_0_) **[THIS LINK IS LITERAL PORN, YOUVE BEEN WARNED]** is called *A Free Ride,* and dates from 1915. These types of works were typically shown in brothels, until film projection equipment became cheap in the 1930s. \n\nAs with photography before it, and books before that, film eventually became cheaper and more widespread, began appearing in the alleyways and under the counter at stores, and eventually lead to arrests, prosecution and jail time. The Czech movie Ecstasy (1933), for example, featured scenes of nudity, and perhaps the first female orgasm shown in a major theatrical release. The scandal of these scenes lead to cries for the seizing and banning of the offensive material, and lead to the Hayes Code in the United States, which successfully banned erotic material from Hollywood movies for the next 30 years. Full freedom of pornographic expression was not available until 1988's California v. Freeman, which effectively legalized hardcore pornography. \n\nOr do you perhaps mean \"porn\" as in the concept of pornography as a whole? 'Porn' as we know it is a relatively recent thing, dating from the early 1800's or so, 1857 is when it was really written into law in our modern understanding of it (in england and France, a few years earlier in America). So 'porn' as we know it is only about 150 years old! \n\nThis is really surprising to most people, as they tend to think, as you do, of the Karma Sutra and other things as pornography. But they're not, or at least in their original contexts they were not\n\n > “the explicit description or exhibition of sexual subjects or activity in literature, painting, films, etc., in a manner intended to stimulate erotic rather than aesthetic feelings” (OED)\n\nAlthough pornography is a Greek word literally meaning “writers about prostitutes,” it is only found once in surviving Ancient Greek writing, where Arthenaeus comments on an artist that painted portraits of whores or courtesans. The word seemed to fall more or less out of use for fifteen hundred years until the first modern usage of the word (1857) to describe erotic wall paintings uncovered at Pompeii. \n\n\nSeveral ‘secret museums’ were founded to house the discoveries. However, these museums (the first of which was the Borbonico museum in Naples) were only accessible to highly educated upper-class men, who could understand Latin and Greek and pay the admission price. \n\n\nAs literacy rose and the book market developed in England and it began to seem possible that anything might be shown to anyone without control, then the ‘shadowy zone’ of pornography was ‘invented,’ regulating the “consumption of the obscene, so as to exclude the lower classes and women.” (Walter Kendrick, p. 57, *The Secret Museum*) Critics and moralists responded to the growing market, rising literacy, and the developing public sphere by expressing a deep anxiety over the impact and influences of erotic works. Erotic discourse began to be inextricably linked to a ’type’ of work that supposedly had undesirous effects upon the English public. In Lynn Hunt’s words then, “pornography as a regulatory category was invented in response to the perceived menace of the democraticization of culture.”\n\n"
]
}
|
[] |
[] |
[
[
"https://commons.wikimedia.org/wiki/File:A_Free_Ride_\\(1915\\).ogv",
"https://www.amazon.com/Annals-Pornographie-How-Porn-Became-ebook/dp/B01CMU51V8",
"https://www.reddit.com/r/AskHistorians/comments/7ez97f/when_did_pornography_come_about_in_human_history/",
"https://www.reddit.com/r/AskHistorians/comments/1cssrf/ama_history_of_pornography_14001800/",
"https://www.reddit.com/r/AskHistorians/comments/1v38ja/what_are_the_earliest_known_pornographic_texts/"
]
] |
|
1wdx7x
|
if buffets are cheaper than having a restaurant with a waiting staff, why aren't all restaurants buffets?
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/1wdx7x/eli5_if_buffets_are_cheaper_than_having_a/
|
{
"a_id": [
"cf126mq",
"cf12adz",
"cf12vd3",
"cf13pbi"
],
"score": [
5,
2,
2,
3
],
"text": [
"It may be cheaper to operate, but that doesn't mean it will make more money or more profit.",
"People won't pay as much for a buffet so you'll probably not make as much profit. ",
"A lot of people prefer sit down restaurants.",
"People enjoy being served. More relaxing and enjoyable to some. Plus the food is better since its made on demand "
]
}
|
[] |
[] |
[
[],
[],
[],
[]
] |
||
798v9m
|
what would happen if one of my eyes are covered for a long time?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/798v9m/eli5_what_would_happen_if_one_of_my_eyes_are/
|
{
"a_id": [
"dp031p3",
"dp03dep"
],
"score": [
3,
5
],
"text": [
"What do you mean by \"a long time\"? Is it half an hour? Half a month? Five years? Twenty years? \n\nIn like 15 minutes, your pupil would dilate(non-native English speaker, is this right? I am thinking expand), letting in more light. Therefore, if you plan on going somewhere dark, or you think it suddenly will become dark where you are, wear an eyepatch on eye. When entering the dark room, switch Wich eye you are covering. Instant night vision.\n\nIf you are talking about covering an eye for more than a day, better find someone else than me.",
"If you are a child and still in a developing stage for vision and perception, covering one of your eyes can cause amblyopia. Amblyopia -a disorder also called lazy eye- causes decreased vision in covered eye due to the interruption in the eye-brain pathway. \nIf done with growing up, i think it is fine to strut around with pirate's eyepatch."
]
}
|
[] |
[] |
[
[],
[]
] |
||
16jslo
|
What's "greener" and/or more energy efficient? Paper towels or Hand Dryers?
|
askscience
|
http://www.reddit.com/r/askscience/comments/16jslo/whats_greener_andor_more_energy_efficient_paper/
|
{
"a_id": [
"c7wphku",
"c7wqv96"
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"score": [
22,
3
],
"text": [
"There are many variables, but electric dryers are lower in cost to operate and, over a lifetime, can be better for the environment (how much depends on paper source, type of dryer, power source...). However, they may not be as hygienic as paper. \n\nAn efficient dryer (like a Dyson Airblade) with a renewable electrical source should always beat paper with transport and disposal costs. \n\n_URL_0_\n\n_URL_1_",
"I'm not certain if this is allowed in here, but this video is relevant: [How To Use a Paper Towel - TED](_URL_0_)"
]
}
|
[] |
[] |
[
[
"http://en.m.wikipedia.org/wiki/Hand_dryer",
"http://www.mayoclinicproceedings.org/article/S0025-6196(12)00393-X/fulltext"
],
[
"http://www.ted.com/talks/joe_smith_how_to_use_a_paper_towel.html"
]
] |
||
117ope
|
Everyone is talking about CO2 and global warming, but could increased water usage (Fossile water from irrigation) make temperature increase?
|
I was wondering this question cause I see all these different irrigation projects in the middle east and other dry areas, and i thought "All that water coming into the cycle can't be that good either."
Is this also a concern?
|
askscience
|
http://www.reddit.com/r/askscience/comments/117ope/everyone_is_talking_about_co2_and_global_warming/
|
{
"a_id": [
"c6k1cq6"
],
"score": [
2
],
"text": [
"Water vapor is a huge greenhouse gas. \n\nWe are more worried about the ocean warming and evaporating more than we are worried about some irrigation operations. \n\nThe ocean has a vastly greater surface area and is much more capable of altering atmospheric moisture content and already is. \n "
]
}
|
[] |
[] |
[
[]
] |
|
kylc3
|
why gifs can't have sound.
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/kylc3/eli5_why_gifs_cant_have_sound/
|
{
"a_id": [
"c2ob6vy",
"c2oejfm",
"c2oiny5",
"c2ob6vy",
"c2oejfm",
"c2oiny5"
],
"score": [
4,
2,
2,
4,
2,
2
],
"text": [
"Gif, jpg, png, mov, avi, mp4 and any other extension you see like that are really just a set of standards. A standard pretty much says, \"act and look this way when this happens, but when this happens do this\"\n\ngif has a standard that doesn't include sound.\n\nFor some more information about these standards, look here: \n[_URL_0_](_URL_0_) (unfortunately gif has no spec on there just yet)\n",
"Gifs are a stack of picture images. Ever tried to get sound out of a flipbook?",
"A file format- any file format, be it GIF, JPEG, PNG, MOV, PDF, whatever- has to be standardised. That is, someone has to dictate exactly what the file is made up of, and everyone has to agree; if they don't, then everyone would make their files differently and everyone would read their files differently, and none of the files would be compatible with anyone else's file viewers.\n\nTo borow from ScoobySnacks801 below, think of the standard for GIF as specifying a stack of still pictures, with a small piece of paper that tells you how quickly to flick through them. By contrast, think of the MOV format as specifying a stack of still pictures, a small piece of paper telling you how quickly to flip through them, and a certain type of audio tape that you should play at the same time at a given speed.\n\nThe GIF format doesn't say anything about an audio tape, so you can't store audio in a GIF. You could certainly add a tape alongside the picture stack, but nobody would know how to play it because there's no standard telling them what kind of tape it is, or where it should start, or how quickly it should play it.\n\nIf you wanted to enough, you could make your own standard; you could tell people that your picture books come with this kind of tape and to play it this fast. But nobody would likely want to bother obeying your rules (making viewers for your file), because nobody but you would use them, and besides, there are formats already that specifiy audio tapes. So instead, you need to use one of those existing formats that do what you want.",
"Gif, jpg, png, mov, avi, mp4 and any other extension you see like that are really just a set of standards. A standard pretty much says, \"act and look this way when this happens, but when this happens do this\"\n\ngif has a standard that doesn't include sound.\n\nFor some more information about these standards, look here: \n[_URL_0_](_URL_0_) (unfortunately gif has no spec on there just yet)\n",
"Gifs are a stack of picture images. Ever tried to get sound out of a flipbook?",
"A file format- any file format, be it GIF, JPEG, PNG, MOV, PDF, whatever- has to be standardised. That is, someone has to dictate exactly what the file is made up of, and everyone has to agree; if they don't, then everyone would make their files differently and everyone would read their files differently, and none of the files would be compatible with anyone else's file viewers.\n\nTo borow from ScoobySnacks801 below, think of the standard for GIF as specifying a stack of still pictures, with a small piece of paper that tells you how quickly to flick through them. By contrast, think of the MOV format as specifying a stack of still pictures, a small piece of paper telling you how quickly to flip through them, and a certain type of audio tape that you should play at the same time at a given speed.\n\nThe GIF format doesn't say anything about an audio tape, so you can't store audio in a GIF. You could certainly add a tape alongside the picture stack, but nobody would know how to play it because there's no standard telling them what kind of tape it is, or where it should start, or how quickly it should play it.\n\nIf you wanted to enough, you could make your own standard; you could tell people that your picture books come with this kind of tape and to play it this fast. But nobody would likely want to bother obeying your rules (making viewers for your file), because nobody but you would use them, and besides, there are formats already that specifiy audio tapes. So instead, you need to use one of those existing formats that do what you want."
]
}
|
[] |
[] |
[
[
"http://www.w3.org/Graphics/"
],
[],
[],
[
"http://www.w3.org/Graphics/"
],
[],
[]
] |
||
6e3tk9
|
Do x-rays occur in nature?
|
askscience
|
https://www.reddit.com/r/askscience/comments/6e3tk9/do_xrays_occur_in_nature/
|
{
"a_id": [
"di7hxzc",
"di7m9hk",
"di7s88q"
],
"score": [
9,
4,
11
],
"text": [
"Absolutely, although when they're of cosmic origin they tend to be called \"Gamma\" radiation. The sun produces x-rays, and Uranium produces it through Compton scattering. More energetic and massively driven events like supernovae can create *vast* outpourings of light in this frequency, as can the activity of a \"feeding\" black hole.",
"There was a study done somewhere showing that certain cellophane tapes could produce xrays simply from peeling it off the roll fast enough. That's not really in nature I suppose but it doesn't require any machine",
"X-rays are high energy photons produced by the acceleration of electrons, while gamma rays are higher energy photons produced by nuclei an other particles.\n\n(In astrophysics, they instead say that x-rays are below some energy and gamma-rays are above. This is because you don't necessarily know what is producing the photons, and because you have to describe your instrument as an X-ray telescope or a gamma-ray telescope based on how it works.)\n\nSome types of radioactive decay produce both gamma rays and x-rays from both the nucleus and the electron cloud.\n\nLightning can produce x-rays, and sometimes even gamma rays.\n\nThe sun produces x-rays even when quiescent because it has a region around it that is much hotte than the surface. It also produces gamma rays during flares.\n\nBlack holes and neutron stars are the most prolific x-ray sources in the sky."
]
}
|
[] |
[] |
[
[],
[],
[]
] |
||
bh8v5b
|
why do car keys (the one with buttons) only unlock your car and none others? not even the same model?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/bh8v5b/eli5_why_do_car_keys_the_one_with_buttons_only/
|
{
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"elqur1f",
"elqur8g",
"elqv6gi",
"elqv7v4",
"elqvdy9",
"elqwank"
],
"score": [
5,
4,
4,
3,
2,
2
],
"text": [
"Small computers that are connected to eachother, they’re called immobilizers and they have specific codes to be in sync with a specific computer in a car",
"Both the car and the key has a chip in it.\n\nthese chips are unique and has been coded to only be able to talk to each other.",
"Your ordinary metal car keys open your car, and other cars too. There are more cars made that your key will fit into than possible keys. These \"radio keys\" are actually more secure, because the number of possible keys is very, very large. Not infinitely large, but much larger than the metal key population times the numbers of cars that will fit into the remote's radio range. There might be one other car that your clicker opens, and your chance of being within the clicker's range is vanishingly small.",
"When you push the button it sends out a small bit of information on a specfic radio channel. A bit inside yourncar is waiting to hear it, and only unlocks the doors if it hears the right password.",
"So it is possible to find a car that my metal key would fit, like start the car. But the car remote can’t unlock any other car except mine?",
"The car and the key are programmed to, basically, ask for a password and state that requested password when the button is pressed. Some cars keep the same one all the time, but some even agree on a new password for each instance of locking/unlocking to prevent the signal's password from being intercepted and cloned."
]
}
|
[] |
[] |
[
[],
[],
[],
[],
[],
[]
] |
||
22faar
|
why are planes round tubes instead of flattened ovals shaped?
|
Would planes fly better and seat more passengers if they were flattened ovals?
Thanks
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/22faar/eli5_why_are_planes_round_tubes_instead_of/
|
{
"a_id": [
"cgm7yth"
],
"score": [
11
],
"text": [
"I'm not an engineer, but structurally cylinders are incredibly strong. An \"flattened tube\" would probably collapse much more easily from all the stresses involved in flight."
]
}
|
[] |
[] |
[
[]
] |
|
68di7v
|
if a person had enough money to design and build a functional space ship, capable of traveling and landing and whatnot, would it be legal? would the government be able to do anything?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/68di7v/eli5_if_a_person_had_enough_money_to_design_and/
|
{
"a_id": [
"dgxn0ny",
"dgxo4vd",
"dgxoboc"
],
"score": [
2,
25,
3
],
"text": [
"The government would most likely not be able to stop you as people have personal planes, helicopters ect. But they would probably try to buy it from you.",
"Well there let's consider these two options.\n\nFirst let's consider that you are just a rich multi-billionaire and want to build a rocket and fly to the moon. Guess what, someone is already doing that. [SpaceX](_URL_0_) is a private company that is building and launching rockets into space right now. They have flown to the International Space Station several times and will soon be carrying passengers. Now SpaceX works closely with NASA and the US government to license operations and flights. BUT if you had enough mony to build a rocket to reach the moon then hiring a few lawyers to jump trough the regulatory hoops would be chump change. [Blue Origin](_URL_2_) is another private company preparing to fly into space.\n\nBottom line: Rocket launches are regulated and licensed by the US government, BUT YES, it is legal for a private citizen to build a rocket and fly into space with the right paperwork. \n\n\nNow let's consider the second option.\n\nLet's say you are a insanely intelligent scientist and discover an entirely new way to fly. Say anti-gravity. So you decide to build an anti-gravity space ship and fly it to the moon. Guess what you can but there are still government issues you would be dealing with. Right now all laws and rules for getting into space are written with rockets in mind. So an anti-gravity powered spacecraft would be considered an aircraft under current us law. Hey it does fly through the air before entering space. So you would have to work with you local [FAA office](_URL_1_) to get an amateur-built aircraft airworthiness certification. Once you built it and were ready to fly it you would have to be properly licensed. Now this is a kicker. There is no license for space craft but you could probably get by if you went and got your private pilots license. But wait you still got one or two more hurdles. If your anti-gravity craft weighed more than 12500 pounds you would need to get a type certificate for it. But guess what that doesn't exist for a anti-gravity craft so you would then have to work with your local field office to get certified to fly the craft you just built. But once all that is done you are ready to go... NOT! there is one more gotcha in US law. US law states that all flights between 18,000 and 60,000 feet in altitude MUST be conducted under IFR, Instrument Flight Rules. So you cant get into space without flying from 18,000 to 60,000 feet. So back to flight school you go to get your Instrument rating. Now you are ready to go. Call your local Flight Service Center and File a IFR flight plan at least 30 minutes before departure. Climb into your space ship and head for the moon. Be sure to contact departure control to activate your flight plan as soon as you are airborne. ",
"If you had enough money to design and build a functional space ship, following all the safety regulations and permits and laws, the government (and many private companies) would probably contract you to deliver some of the satellites and supplies and science projects / scientists to space.\n\nThat's what SpaceX and other private companies are doing."
]
}
|
[] |
[] |
[
[],
[
"http://www.spacex.com/",
"https://www.faa.gov/aircraft/gen_av/ultralights/amateur_built/aw/",
"https://www.blueorigin.com/"
],
[]
] |
||
ayj6k7
|
How did people light candles before the invention of matches/lighters?
|
The title pretty much covers it: how did they do it? The only rudimentary ways of lighting fires (mirrors, flint and steel, friction, etc) I can think of wouldn't work on a candle wick, at least not effectively, so how did they light candles?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/ayj6k7/how_did_people_light_candles_before_the_invention/
|
{
"a_id": [
"ei6w77k"
],
"score": [
3
],
"text": [
"Starting from a \"there's no fire nearby\" state would require breaking out a tinderbox and flint and steel. You would strike sparks from the flint and steel into material that would be highly susceptible to catching fire. This might be something super low tech such as ordinary tinder like wood shavings, dry pine needles, or what-have-you. It could be a little bit more sophisticated like chunks of charred wood left over from an old fire (or proper charcoal) or char cloth (the equivalent of charcoal except in cloth form). Once you have smoldering happening in your tinder then you could blow on it to encourage it to come up to a full flame, which you could then transfer elsewhere via a small wood splint or twig. Or if you have a candle you could use the heat to melt some of the wax into your smoldering tinder, which will light more easily, and then use that to catch the wick of the candle.\n\nKeep in mind that the effective labor involved here is not just in the work described above but also in using up some of the materials (tinder, char cloth, etc.) which take labor to replace. So you'd generally avoid having to start a fire when possible. In a home you'd often keep a fire running all day and night, or perhaps simply \"banked\" overnight (hot coals covered and slowly cooling, ready to be used to start a new fire in the morning with just the addition of tinder, air, and some TLC). Then you'd simply light lamps and candles via splints you lit from the fire.\n\nToolkits similar to this (flint, steel, tinder) have been commonly in use since at least the Bronze Age if not longer. Otzi the ice man was found to have both flint and pyrite (for making sparks) as well as a tinder fungus (prepared into sheets)."
]
}
|
[] |
[] |
[
[]
] |
|
25mjy0
|
the california energy crisis of 2000 and the enron scandal
|
explainlikeimfive
|
http://www.reddit.com/r/explainlikeimfive/comments/25mjy0/eli5_the_california_energy_crisis_of_2000_and_the/
|
{
"a_id": [
"chimpjc",
"chinil4"
],
"score": [
5,
3
],
"text": [
"As for the energy crisis, basically Enron would cut off the power supply so that the cost of electricity would skyrocket, and then turn it back on in order to make more money. Enron in general, that was mostly down to a type of accounting they used that let them declare potential earnings, so that it always looked like they were making loads of money when they were, in fact, losing money. I would recommend the documentary \"The smartest men in the room\" If you want to learn more",
"Enron was an energy company that engaged in a lot of fraudulent accounting tricks to make it look like they were much more profitable than they were. It wasn't a complete fraud like Madoff - they had some legitimate businesses like pipelines and actually did produce electricity, but they also had a lot of pie-in-the-sky ideas, most of which lost a ton of money. And when those schemes lost money, instead of admitting it, they either lied about it or used more accounting tricks to hide the losses. When they were losing too much money, it became too hard to maintain their shell game of hiding losses and moving them around, and sooner or later it was clear that the company was in trouble, and investors lost confidence in the company and started selling the stock. When the stock price started declining, it became impossible to maintain the accounting tricks, because they couldn't do things like use overvalued stock as collateral for loans. They went from being one of the ten largest U.S. companies by stock market capitalization to being bankrupt in about 18 months.\n\nEnron was a major factor in the California energy crisis of 2000, but they weren't the sole cause of it. During a heat wave where demand for electricity soared, Enron created artificial shortages of power in order to be able to jack up the price."
]
}
|
[] |
[] |
[
[],
[]
] |
||
pu1xa
|
How do groups of photons form electromagnetic waves?
|
askscience
|
http://www.reddit.com/r/askscience/comments/pu1xa/how_do_groups_of_photons_form_electromagnetic/
|
{
"a_id": [
"c3s8vry"
],
"score": [
2
],
"text": [
"You are mixing two concepts. Photons have both wave-like and particle-like properties. It is not the case that adding up the particle-properties (the quantized packets) yields the wave-like behavior. \n\n_URL_0_"
]
}
|
[] |
[] |
[
[
"http://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality"
]
] |
||
3fxw8t
|
Has an American President, after serving his term, ever served on a jury?
|
A rather funny comment in this thread ( _URL_0_ ) has my curious. Has an American president, after serving his term, ever served on a jury?
|
AskHistorians
|
http://www.reddit.com/r/AskHistorians/comments/3fxw8t/has_an_american_president_after_serving_his_term/
|
{
"a_id": [
"ctt17xr"
],
"score": [
18
],
"text": [
" > In fact, no modern court has had a sitting president on a jury. Ronald Reagan came the closest when he was summoned in the 1980s by Santa Barbara County, Calif. He was granted a deferment until he was out of office.\n\n[Source 1](_URL_3_)\n\n[Source 2 - Former POTUS G.W. Bush's duty](_URL_0_)\n\nThat photo is good 'ole W actually serving his duty as a juror, so yes! \n\nRelevant Statute(s):\n\n-2 U.S. Code §* 30a - Jury duty exemption of elected officials of legislative branch:\n\nsubsection (a): \"Notwithstanding any other provision of Federal, State or local law, no elected official of the **legislative branch of the United States Government** shall be required to serve on a grand or petit jury, convened by any Federal, State or local court, whether such service is requested by judicial summons or by some other means of compulsion.\"\n\n-28 U.S. Code § 1866 - Selection and summoning of jury panels:\n\nSubsection (c)(1): \" excused by the court, or by the clerk under supervision of the court if the court’s jury selection plan so authorizes, upon a showing of undue hardship or extreme inconvenience...\"\n\nSubsection (c)(2): \"excluded by the court on the ground that such person may be unable to render impartial jury service or that his service as a juror would be likely to disrupt the proceedings...\"\n\n*§ = \"Paragraph\"; bolded text my emphasis\n\nSources:\n\n[2 US Code 30a](_URL_2_)\n\n[28 US Code para 1866](_URL_1_)\n\nHas it happened to a former president? ~~Indeed~~ Sort of. *Can* it happen to a sitting president? Technically, yes, but in reality its a long shot! Presidents, serving or otherwise, *are not members of the legislative branch*, but of the Executive branch. Naturally of course, a barrister conducting jury selection will have quite a feat on their hands trying to convince all involved that the POTUS or Ex-POTUS is both not greatly inconvenienced nor capable of gross bias in any instance."
]
}
|
[] |
[
"https://www.reddit.com/r/pics/comments/3fwhjj/look_who_my_friend_has_jury_duty_with_today/ctslrw1"
] |
[
[
"http://time.com/3986224/george-w-bush-jury-duty/",
"https://www.law.cornell.edu/uscode/text/28/1866",
"https://www.law.cornell.edu/uscode/text/2/30a",
"http://www.csmonitor.com/2006/0110/p01s03-uspo.html"
]
] |
|
4wpp63
|
Border between East Germany and Czechoslovak Socialist Republic during Cold War
|
Were there formal border crossings or a 'wall' between East Germany and the Czechoslovak Socialist Republic during the Cold War? Would it have been relatively easy for someone from East Germany to travel to the other socialist state or would they have needed to apply for a visa / go through inspection at the border before they could travel?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/4wpp63/border_between_east_germany_and_czechoslovak/
|
{
"a_id": [
"d6921lb",
"d6939kc"
],
"score": [
4,
5
],
"text": [
"There was no special permission required for Czechoslovaks during the Communist era to travel to other Eastern Bloc countries, including the GDR. This does not mean, however, that one could just waltz across the border, which was certainly patrolled, although not barbed-wired to the extent that the borders with West Germany or Austria were. Definitely not some kind of socialist Schengen area. It is probably fair to say that the purpose of those borders were to deter smugglers rather than emigrants. Czechoslovaks traveled to the GDR quite frequently, usually on trips organized by one of the state travel agencies, which would organize all the necessary documents for them. ",
"For citizens of the GDR (German Democratic Republic), foreign countries were divided into two categories: 1) 'Socialist Countries' and 2) 'Not Socialist Countries'. \n\nBetween the GDR and the CSSR there was a formal border crossing, but no special visas were required. What was somewhat difficult was changing money, which could be done in certain amounts. No country wanted the worthless currency of the other country. If one had D-Mark (which was the de-facto hard currency), then one could easily change on the black market. \n\nCitizens of the GDR living near the CSSR would make unofficial 'shopping trips' into the CSSR to buy certain goods which were cheaper or even available. But one had to be discreet about such shopping trips. \n\nFor Poland, there were no strict visa regulations until 1980. After 1980 the visa process for Poland became very complicated. Other fellow Socialist countries, like Hungary, Romania and Bulgaria were visited as summer holiday destinations. Of these countries, Hungary was very expensive for GDR citizens but the most interesting. \n\nAs mentioned before, the biggest headache for traveling abroad for GDR citizens was the currency exchange -- GDR citizens were only allowed to exchange a certain amount of money every year. To avoid such headaches, many just took their summer holidays in the GDR itself. Many state-owned companies provided their workers with summer holiday accommodation as well. \n\nTraveling to 'Not Socialist Countries' was far more complicated and involved a long visa process. \n\nRecommended reading (in German): 'Urlaub vom Staat: Tourismus in der DDR'. (C. Goerlich). "
]
}
|
[] |
[] |
[
[],
[]
] |
|
friep3
|
Did the SS take measures to reduce the spread of infection to themselves during the Holocaust?
|
The camps during the Holocaust were prime breeding grounds for diseases to spread through them. Did the SS have any measures to make sure that they themselves did not become infected? If so what were they?
|
AskHistorians
|
https://www.reddit.com/r/AskHistorians/comments/friep3/did_the_ss_take_measures_to_reduce_the_spread_of/
|
{
"a_id": [
"flwi2fg"
],
"score": [
11
],
"text": [
"The camps were designed to run with a minimum of SS personnel and not so much personal contact.\n\nKapos were frequently employed to keep order and handle a lot of the day to day business of the camp, including punishments and physical abuse. Kapos were prisoners themselves but they earned special privileges such as better food, housing, and freedom from abuse in return for working for the SS administrators. The average SS man at a concentration camp would not really need to come into close contact with many prisoners, and thus the camps could be run with a skeleton crew of SS men with a lot of local enforcers.\n\nThe most distasteful of tasks, such as preparing and cleaning out the gas chambers was assigned to the Sonderkommando, a work unit made up of camp inmates. They were not necessarily a 'disciplinary' unit like the Kapos but were instead doing a horrid and distasteful job that put them in close contact with lots of corpses. Sonderkommando were kept apart from the rest of the inmates and also given slightly better conditions in order to keep them strong enough to work. The Sonderkommando were not as privileged as the Kapos, and would soon find themselves in the very same gas chambers they knew all too well. It would be the first job of the new 'generation' of Sonderkommando to dispose of the previous one. The Sonderkommando men 'knew too much' and so were disposed of and replaced with a new crew after a few months. Some of them managed to smuggle messages detailing the horror they witnessed and participated in out of the camps. \n\nAs you can see, much of the nitty-gritty of running a death-camp is passed down as a duty of the prisoners themselves. Refusing to work for the Nazis would certainly ensure you severe consequences. Working for them would give you a chance to possibly survive, at the cost of betraying your fellow inmates. Some people did this for pure opportunism, others were hateful anti-Semites (camps had a wide range of people, and not just Jews), while others were simply doing anything they can to survive. It is hard to judge them from afar without knowing what it is like to be cold and starving to death and to be offered a job that might improve your situation at the cost of your fellow prisoners."
]
}
|
[] |
[] |
[
[]
] |
|
89snwm
|
can anyone launch a satellite? or are there laws claiming space territory?
|
With the FCC approving spaceX to launch all those satellites why would they even need approval? Is space not borderless?
|
explainlikeimfive
|
https://www.reddit.com/r/explainlikeimfive/comments/89snwm/eli5can_anyone_launch_a_satellite_or_are_there/
|
{
"a_id": [
"dwt838a"
],
"score": [
5
],
"text": [
"Per the [Outer Space Treaty](_URL_0_) of 1967, governments cannot stake a claim to territory in space—so yes, space is indeed borderless. However, to get to outer space, Spacex's rockets first have to pass through the airspace directly above the US, which the Federal Aviation Administration *does* have jurisdiction over, thus requiring their approval."
]
}
|
[] |
[] |
[
[
"https://en.wikipedia.org/wiki/Outer_Space_Treaty"
]
] |
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